1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
|
<!DOCTYPE html>
<!--[if IE 8]><html class="no-js lt-ie9" lang="en" > <![endif]-->
<!--[if gt IE 8]><!--> <html class="no-js" lang="en" > <!--<![endif]-->
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Helper Functions — CodeIgniter 3.1.8 documentation</title>
<link rel="shortcut icon" href="../_static/ci-icon.ico"/>
<link href='https://fonts.googleapis.com/css?family=Lato:400,700,400italic,700italic|Roboto+Slab:400,700|Inconsolata:400,700&subset=latin,cyrillic' rel='stylesheet' type='text/css'>
<link rel="stylesheet" href="../_static/css/citheme.css" type="text/css" />
<link rel="index" title="Index"
href="../genindex.html"/>
<link rel="search" title="Search" href="../search.html"/>
<link rel="top" title="CodeIgniter 3.1.8 documentation" href="../index.html"/>
<link rel="up" title="General Topics" href="index.html"/>
<link rel="next" title="Using CodeIgniter Libraries" href="libraries.html"/>
<link rel="prev" title="Models" href="models.html"/>
<script src="https://cdnjs.cloudflare.com/ajax/libs/modernizr/2.6.2/modernizr.min.js"></script>
</head>
<body class="wy-body-for-nav" role="document">
<div id="nav">
<div id="nav_inner">
<div id="pulldown-menu" class="ciNav">
<ul>
<li class="toctree-l1"><a class="reference internal" href="welcome.html">Welcome to CodeIgniter</a></li>
</ul>
<ul>
<li class="toctree-l1"><a class="reference internal" href="../installation/index.html">Installation Instructions</a><ul>
<li class="toctree-l2"><a class="reference internal" href="../installation/downloads.html">Downloading CodeIgniter</a></li>
<li class="toctree-l2"><a class="reference internal" href="../installation/index.html">Installation Instructions</a></li>
<li class="toctree-l2"><a class="reference internal" href="../installation/upgrading.html">Upgrading From a Previous Version</a></li>
<li class="toctree-l2"><a class="reference internal" href="../installation/troubleshooting.html">Troubleshooting</a></li>
</ul>
</li>
</ul>
<ul>
<li class="toctree-l1"><a class="reference internal" href="../overview/index.html">CodeIgniter Overview</a><ul>
<li class="toctree-l2"><a class="reference internal" href="../overview/getting_started.html">Getting Started</a></li>
<li class="toctree-l2"><a class="reference internal" href="../overview/at_a_glance.html">CodeIgniter at a Glance</a></li>
<li class="toctree-l2"><a class="reference internal" href="../overview/features.html">Supported Features</a></li>
<li class="toctree-l2"><a class="reference internal" href="../overview/appflow.html">Application Flow Chart</a></li>
<li class="toctree-l2"><a class="reference internal" href="../overview/mvc.html">Model-View-Controller</a></li>
<li class="toctree-l2"><a class="reference internal" href="../overview/goals.html">Architectural Goals</a></li>
</ul>
</li>
</ul>
<ul>
<li class="toctree-l1"><a class="reference internal" href="../tutorial/index.html">Tutorial</a><ul>
<li class="toctree-l2"><a class="reference internal" href="../tutorial/static_pages.html">Static pages</a></li>
<li class="toctree-l2"><a class="reference internal" href="../tutorial/news_section.html">News section</a></li>
<li class="toctree-l2"><a class="reference internal" href="../tutorial/create_news_items.html">Create news items</a></li>
<li class="toctree-l2"><a class="reference internal" href="../tutorial/conclusion.html">Conclusion</a></li>
</ul>
</li>
</ul>
<ul>
<li class="toctree-l1"><a class="reference internal" href="../contributing/index.html">Contributing to CodeIgniter</a><ul>
<li class="toctree-l2"><a class="reference internal" href="../documentation/index.html">Writing CodeIgniter Documentation</a></li>
<li class="toctree-l2"><a class="reference internal" href="../DCO.html">Developer’s Certificate of Origin 1.1</a></li>
</ul>
</li>
</ul>
<ul class="current">
<li class="toctree-l1 current"><a class="reference internal" href="index.html">General Topics</a><ul class="current">
<li class="toctree-l2"><a class="reference internal" href="urls.html">CodeIgniter URLs</a></li>
<li class="toctree-l2"><a class="reference internal" href="controllers.html">Controllers</a></li>
<li class="toctree-l2"><a class="reference internal" href="reserved_names.html">Reserved Names</a></li>
<li class="toctree-l2"><a class="reference internal" href="views.html">Views</a></li>
<li class="toctree-l2"><a class="reference internal" href="models.html">Models</a></li>
<li class="toctree-l2 current"><a class="current reference internal" href="#">Helpers</a></li>
<li class="toctree-l2"><a class="reference internal" href="libraries.html">Using CodeIgniter Libraries</a></li>
<li class="toctree-l2"><a class="reference internal" href="creating_libraries.html">Creating Libraries</a></li>
<li class="toctree-l2"><a class="reference internal" href="drivers.html">Using CodeIgniter Drivers</a></li>
<li class="toctree-l2"><a class="reference internal" href="creating_drivers.html">Creating Drivers</a></li>
<li class="toctree-l2"><a class="reference internal" href="core_classes.html">Creating Core System Classes</a></li>
<li class="toctree-l2"><a class="reference internal" href="ancillary_classes.html">Creating Ancillary Classes</a></li>
<li class="toctree-l2"><a class="reference internal" href="hooks.html">Hooks - Extending the Framework Core</a></li>
<li class="toctree-l2"><a class="reference internal" href="autoloader.html">Auto-loading Resources</a></li>
<li class="toctree-l2"><a class="reference internal" href="common_functions.html">Common Functions</a></li>
<li class="toctree-l2"><a class="reference internal" href="compatibility_functions.html">Compatibility Functions</a></li>
<li class="toctree-l2"><a class="reference internal" href="routing.html">URI Routing</a></li>
<li class="toctree-l2"><a class="reference internal" href="errors.html">Error Handling</a></li>
<li class="toctree-l2"><a class="reference internal" href="caching.html">Caching</a></li>
<li class="toctree-l2"><a class="reference internal" href="profiling.html">Profiling Your Application</a></li>
<li class="toctree-l2"><a class="reference internal" href="cli.html">Running via the CLI</a></li>
<li class="toctree-l2"><a class="reference internal" href="managing_apps.html">Managing your Applications</a></li>
<li class="toctree-l2"><a class="reference internal" href="environments.html">Handling Multiple Environments</a></li>
<li class="toctree-l2"><a class="reference internal" href="alternative_php.html">Alternate PHP Syntax for View Files</a></li>
<li class="toctree-l2"><a class="reference internal" href="security.html">Security</a></li>
<li class="toctree-l2"><a class="reference internal" href="styleguide.html">PHP Style Guide</a></li>
</ul>
</li>
</ul>
<ul>
<li class="toctree-l1"><a class="reference internal" href="../libraries/index.html">Libraries</a><ul>
<li class="toctree-l2"><a class="reference internal" href="../libraries/benchmark.html">Benchmarking Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/caching.html">Caching Driver</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/calendar.html">Calendaring Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/cart.html">Shopping Cart Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/config.html">Config Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/email.html">Email Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/encrypt.html">Encrypt Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/encryption.html">Encryption Library</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/file_uploading.html">File Uploading Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/form_validation.html">Form Validation</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/ftp.html">FTP Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/image_lib.html">Image Manipulation Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/input.html">Input Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/javascript.html">Javascript Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/language.html">Language Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/loader.html">Loader Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/migration.html">Migrations Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/output.html">Output Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/pagination.html">Pagination Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/parser.html">Template Parser Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/security.html">Security Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/sessions.html">Session Library</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/table.html">HTML Table Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/trackback.html">Trackback Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/typography.html">Typography Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/unit_testing.html">Unit Testing Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/uri.html">URI Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/user_agent.html">User Agent Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/xmlrpc.html">XML-RPC and XML-RPC Server Classes</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/zip.html">Zip Encoding Class</a></li>
</ul>
</li>
</ul>
<ul>
<li class="toctree-l1"><a class="reference internal" href="../database/index.html">Database Reference</a><ul>
<li class="toctree-l2"><a class="reference internal" href="../database/examples.html">Quick Start: Usage Examples</a></li>
<li class="toctree-l2"><a class="reference internal" href="../database/configuration.html">Database Configuration</a></li>
<li class="toctree-l2"><a class="reference internal" href="../database/connecting.html">Connecting to a Database</a></li>
<li class="toctree-l2"><a class="reference internal" href="../database/queries.html">Running Queries</a></li>
<li class="toctree-l2"><a class="reference internal" href="../database/results.html">Generating Query Results</a></li>
<li class="toctree-l2"><a class="reference internal" href="../database/helpers.html">Query Helper Functions</a></li>
<li class="toctree-l2"><a class="reference internal" href="../database/query_builder.html">Query Builder Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../database/transactions.html">Transactions</a></li>
<li class="toctree-l2"><a class="reference internal" href="../database/metadata.html">Getting MetaData</a></li>
<li class="toctree-l2"><a class="reference internal" href="../database/call_function.html">Custom Function Calls</a></li>
<li class="toctree-l2"><a class="reference internal" href="../database/caching.html">Query Caching</a></li>
<li class="toctree-l2"><a class="reference internal" href="../database/forge.html">Database Manipulation with Database Forge</a></li>
<li class="toctree-l2"><a class="reference internal" href="../database/utilities.html">Database Utilities Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../database/db_driver_reference.html">Database Driver Reference</a></li>
</ul>
</li>
</ul>
<ul>
<li class="toctree-l1"><a class="reference internal" href="../helpers/index.html">Helpers</a><ul>
<li class="toctree-l2"><a class="reference internal" href="../helpers/array_helper.html">Array Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/captcha_helper.html">CAPTCHA Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/cookie_helper.html">Cookie Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/date_helper.html">Date Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/directory_helper.html">Directory Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/download_helper.html">Download Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/email_helper.html">Email Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/file_helper.html">File Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/form_helper.html">Form Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/html_helper.html">HTML Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/inflector_helper.html">Inflector Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/language_helper.html">Language Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/number_helper.html">Number Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/path_helper.html">Path Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/security_helper.html">Security Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/smiley_helper.html">Smiley Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/string_helper.html">String Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/text_helper.html">Text Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/typography_helper.html">Typography Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/url_helper.html">URL Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/xml_helper.html">XML Helper</a></li>
</ul>
</li>
</ul>
</div>
</div>
</div>
<div id="nav2">
<a href="#" id="openToc">
<img src="data:image/jpeg;base64,/9j/4AAQSkZJRgABAgAAZABkAAD/7AARRHVja3kAAQAEAAAARgAA/+4ADkFkb2JlAGTAAAAAAf/bAIQABAMDAwMDBAMDBAYEAwQGBwUEBAUHCAYGBwYGCAoICQkJCQgKCgwMDAwMCgwMDQ0MDBERERERFBQUFBQUFBQUFAEEBQUIBwgPCgoPFA4ODhQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQU/8AAEQgAKwCaAwERAAIRAQMRAf/EAHsAAQAABwEBAAAAAAAAAAAAAAABAwQFBgcIAgkBAQAAAAAAAAAAAAAAAAAAAAAQAAEDAwICBwYEAgsAAAAAAAIBAwQAEQUSBiEHkROTVNQWGDFBUVIUCHEiMtOUFWGBobHRQlMkZIRVEQEAAAAAAAAAAAAAAAAAAAAA/9oADAMBAAIRAxEAPwDSC+ygkOOaUoKigUCgUCgUCgUCgUCgUCgUCgkuGguIP9FBMFb0Hqg7We+3jlmIqqYFf4ub+/QYlnOR/LqIBKGFUbf8qWv971BytQXXE7Y3Lnm3HsFhp2TaZJAdchRXpIgSpdEJWxJEW3xoKV7F5OMy7JkQn2o7D6w33XGjEAkoiqrJEqIiOIiKuhePCgqp22dyYyS3CyWHnQ5joG61HkRnmnTbaFSMhExRVQRRVJU9iUHjE7ez+fJ0MFipmUNhBV8YUd2SoIV9KkjQla9ltegttBdPLW4/qocL+UTfrMiHW4+P9M71shuyrqaHTcxsl7jegpsji8nh5ZwMvDfgTm0RTjSmjYdFCS6KoOIipdFunCgmNYTMv457MMY6U7iI6oMieDDhRm1VbIhuoOkbqtuK0Hpzb+eZcYZexUxt6UyUqK2cd0SdjtgrhOgijcgERUlJOCIl6CpgbP3blRI8XgMjNARAyKNDfeRBdFDBVUAXgQrqH4pxoJTu2NysY97LP4ac1io5q1InHFeGO24LnVKJuKOkSQ/yKir+rh7aCLG1dzypZQI2FnvTgccYOM3FeN0XWERXAUEFVQgQkUktdLpegm+Td3/Xli/L+S/mYNJIOF9G/wBeLKrZHFb0akG6W1WtQWSg3Dyg5e7V3fipE3O4/wCrktyzYA+ufas2LbZIlmnAT2kvuoN1wft95augilglX/tzP3qCu9O3LL/wV/i5v79BvmTADq14UGu91467Z6U9y0HzH/ncj/U/sT/CgynZG7I2NezpZGUjIycJkYkZSG+uQ81pbBNKLxJfjwoMqZ3/ALYHl35AJ7/cuwHcu5k7r1Q5pHetBjquqVVJWGxj9Zrtcl/Ggy3dHMvauR3HFZj5nHNxSyW5JISYDMoIwx8tFIGHZhPNaykGapr6rUAiicEoMG21lMRj8buPAz8xhJrr7uOeiPTCyAwXUaGR1mgozbTusOsFLEiJ7fbQa/h7gcjy2H3V6xppwDNtUSxCJIqp7valBuWVzJ22xuCROXNNZiJkMtms0DbjUkAZjzoDrTMd9dDRI44ZC2YsrYdKWP2WDT2S3N9dNdlRYrGMYc06IURXSYb0igrpWS485xVNS6nF4rwslkoMwnbpgZLB7bmt5uMweAhDEl4B5uSLzzqTnnyVpW2jaJHRMSIjdDiiotvy3DOE5rYTEbkl5yFn28k7JyG4c7AU2HtLH1uKfaiMPI40CdYbpNtmLdwTSn5rewLNld+7TLdeal4WarWBkbVKBjgdElMJJwAAY5fl4kB3b1fp4XvagsGS3FjJfLzDNtS8aeXx7LzT7TyzByQE5PccRGRC0ZRUDRV6y62vbjagzLmJzS2vuPK43JY6aP1TW6Jz+RIWyFtyC06y3EkiiinAo7YCqfq1AqqnGgsOH3lhZO8d1pmcpB8j5XIm9OYlBJSQ/FSS4427DKO0RC8AlcEMhFdViRR1WDWR5t3WXVuL1d106kG9vdeye2g60+1FDyW0shIcXVpyroXt8I8dfd+NB1vioAdWnD3UF1+gD4UFc6CEKpagxXN43rwJLUHz7yX2c8zokt9uHlsPIhA4aRnnHJTLptIS6CNsY7iASpxUUMkReGpfbQW0vtN5pitvrsN28rwtBD0nc0+/Yft5XhaB6TuaXfsP28rwtA9J3NPv2H7eV4Wgek7mn37D9vK8LQPSdzT79h+3leFoHpO5pd+w/byvC0D0nc0u/Yft5XhaB6TuaXfsP28rwtA9J3NLv2H7eV4Wgek7ml37D9vK8LQPSdzS79h+3leFoHpO5p9+w/byvC0E9r7Reazy2HIYVPxkS/CUHVn26cosxyv2g7h89LYmZSXOenvLEQ1YaQ222RATcQCP8rSGqqA8S02W2pQ6FhMoAIlqCtsnwoCpdKClejI4i3Sgtb+GBxVuNBSFt1pV/RQefLjPyUDy4z8lA8uM/JQPLjPyUDy4z8lA8uM/JQPLjPyUDy4z8lA8uM/JQPLjPyUDy4z8lA8utJ/koJ7WCbBU/LQXOPAFq1koK8B0pag90CggtBBf6qB0UDooHRQOigdFA6KB0UDooHRQOigdFA6KB0UDooI0EaBQf//Z" title="Toggle Table of Contents" alt="Toggle Table of Contents" />
</a>
</div>
<div class="wy-grid-for-nav">
<nav data-toggle="wy-nav-shift" class="wy-nav-side">
<div class="wy-side-nav-search">
<a href="../index.html" class="fa fa-home"> CodeIgniter</a>
<div role="search">
<form id="rtd-search-form" class="wy-form" action="../search.html" method="get">
<input type="text" name="q" placeholder="Search docs" />
<input type="hidden" name="check_keywords" value="yes" />
<input type="hidden" name="area" value="default" />
</form>
</div>
</div>
<div class="wy-menu wy-menu-vertical" data-spy="affix" role="navigation" aria-label="main navigation">
<ul>
<li class="toctree-l1"><a class="reference internal" href="welcome.html">Welcome to CodeIgniter</a></li>
</ul>
<ul>
<li class="toctree-l1"><a class="reference internal" href="../installation/index.html">Installation Instructions</a><ul>
<li class="toctree-l2"><a class="reference internal" href="../installation/downloads.html">Downloading CodeIgniter</a></li>
<li class="toctree-l2"><a class="reference internal" href="../installation/index.html">Installation Instructions</a></li>
<li class="toctree-l2"><a class="reference internal" href="../installation/upgrading.html">Upgrading From a Previous Version</a></li>
<li class="toctree-l2"><a class="reference internal" href="../installation/troubleshooting.html">Troubleshooting</a></li>
</ul>
</li>
</ul>
<ul>
<li class="toctree-l1"><a class="reference internal" href="../overview/index.html">CodeIgniter Overview</a><ul>
<li class="toctree-l2"><a class="reference internal" href="../overview/getting_started.html">Getting Started</a></li>
<li class="toctree-l2"><a class="reference internal" href="../overview/at_a_glance.html">CodeIgniter at a Glance</a></li>
<li class="toctree-l2"><a class="reference internal" href="../overview/features.html">Supported Features</a></li>
<li class="toctree-l2"><a class="reference internal" href="../overview/appflow.html">Application Flow Chart</a></li>
<li class="toctree-l2"><a class="reference internal" href="../overview/mvc.html">Model-View-Controller</a></li>
<li class="toctree-l2"><a class="reference internal" href="../overview/goals.html">Architectural Goals</a></li>
</ul>
</li>
</ul>
<ul>
<li class="toctree-l1"><a class="reference internal" href="../tutorial/index.html">Tutorial</a><ul>
<li class="toctree-l2"><a class="reference internal" href="../tutorial/static_pages.html">Static pages</a></li>
<li class="toctree-l2"><a class="reference internal" href="../tutorial/news_section.html">News section</a></li>
<li class="toctree-l2"><a class="reference internal" href="../tutorial/create_news_items.html">Create news items</a></li>
<li class="toctree-l2"><a class="reference internal" href="../tutorial/conclusion.html">Conclusion</a></li>
</ul>
</li>
</ul>
<ul>
<li class="toctree-l1"><a class="reference internal" href="../contributing/index.html">Contributing to CodeIgniter</a><ul>
<li class="toctree-l2"><a class="reference internal" href="../documentation/index.html">Writing CodeIgniter Documentation</a></li>
<li class="toctree-l2"><a class="reference internal" href="../DCO.html">Developer’s Certificate of Origin 1.1</a></li>
</ul>
</li>
</ul>
<ul class="current">
<li class="toctree-l1 current"><a class="reference internal" href="index.html">General Topics</a><ul class="current">
<li class="toctree-l2"><a class="reference internal" href="urls.html">CodeIgniter URLs</a></li>
<li class="toctree-l2"><a class="reference internal" href="controllers.html">Controllers</a></li>
<li class="toctree-l2"><a class="reference internal" href="reserved_names.html">Reserved Names</a></li>
<li class="toctree-l2"><a class="reference internal" href="views.html">Views</a></li>
<li class="toctree-l2"><a class="reference internal" href="models.html">Models</a></li>
<li class="toctree-l2 current"><a class="current reference internal" href="#">Helpers</a></li>
<li class="toctree-l2"><a class="reference internal" href="libraries.html">Using CodeIgniter Libraries</a></li>
<li class="toctree-l2"><a class="reference internal" href="creating_libraries.html">Creating Libraries</a></li>
<li class="toctree-l2"><a class="reference internal" href="drivers.html">Using CodeIgniter Drivers</a></li>
<li class="toctree-l2"><a class="reference internal" href="creating_drivers.html">Creating Drivers</a></li>
<li class="toctree-l2"><a class="reference internal" href="core_classes.html">Creating Core System Classes</a></li>
<li class="toctree-l2"><a class="reference internal" href="ancillary_classes.html">Creating Ancillary Classes</a></li>
<li class="toctree-l2"><a class="reference internal" href="hooks.html">Hooks - Extending the Framework Core</a></li>
<li class="toctree-l2"><a class="reference internal" href="autoloader.html">Auto-loading Resources</a></li>
<li class="toctree-l2"><a class="reference internal" href="common_functions.html">Common Functions</a></li>
<li class="toctree-l2"><a class="reference internal" href="compatibility_functions.html">Compatibility Functions</a></li>
<li class="toctree-l2"><a class="reference internal" href="routing.html">URI Routing</a></li>
<li class="toctree-l2"><a class="reference internal" href="errors.html">Error Handling</a></li>
<li class="toctree-l2"><a class="reference internal" href="caching.html">Caching</a></li>
<li class="toctree-l2"><a class="reference internal" href="profiling.html">Profiling Your Application</a></li>
<li class="toctree-l2"><a class="reference internal" href="cli.html">Running via the CLI</a></li>
<li class="toctree-l2"><a class="reference internal" href="managing_apps.html">Managing your Applications</a></li>
<li class="toctree-l2"><a class="reference internal" href="environments.html">Handling Multiple Environments</a></li>
<li class="toctree-l2"><a class="reference internal" href="alternative_php.html">Alternate PHP Syntax for View Files</a></li>
<li class="toctree-l2"><a class="reference internal" href="security.html">Security</a></li>
<li class="toctree-l2"><a class="reference internal" href="styleguide.html">PHP Style Guide</a></li>
</ul>
</li>
</ul>
<ul>
<li class="toctree-l1"><a class="reference internal" href="../libraries/index.html">Libraries</a><ul>
<li class="toctree-l2"><a class="reference internal" href="../libraries/benchmark.html">Benchmarking Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/caching.html">Caching Driver</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/calendar.html">Calendaring Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/cart.html">Shopping Cart Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/config.html">Config Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/email.html">Email Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/encrypt.html">Encrypt Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/encryption.html">Encryption Library</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/file_uploading.html">File Uploading Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/form_validation.html">Form Validation</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/ftp.html">FTP Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/image_lib.html">Image Manipulation Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/input.html">Input Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/javascript.html">Javascript Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/language.html">Language Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/loader.html">Loader Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/migration.html">Migrations Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/output.html">Output Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/pagination.html">Pagination Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/parser.html">Template Parser Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/security.html">Security Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/sessions.html">Session Library</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/table.html">HTML Table Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/trackback.html">Trackback Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/typography.html">Typography Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/unit_testing.html">Unit Testing Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/uri.html">URI Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/user_agent.html">User Agent Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/xmlrpc.html">XML-RPC and XML-RPC Server Classes</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/zip.html">Zip Encoding Class</a></li>
</ul>
</li>
</ul>
<ul>
<li class="toctree-l1"><a class="reference internal" href="../database/index.html">Database Reference</a><ul>
<li class="toctree-l2"><a class="reference internal" href="../database/examples.html">Quick Start: Usage Examples</a></li>
<li class="toctree-l2"><a class="reference internal" href="../database/configuration.html">Database Configuration</a></li>
<li class="toctree-l2"><a class="reference internal" href="../database/connecting.html">Connecting to a Database</a></li>
<li class="toctree-l2"><a class="reference internal" href="../database/queries.html">Running Queries</a></li>
<li class="toctree-l2"><a class="reference internal" href="../database/results.html">Generating Query Results</a></li>
<li class="toctree-l2"><a class="reference internal" href="../database/helpers.html">Query Helper Functions</a></li>
<li class="toctree-l2"><a class="reference internal" href="../database/query_builder.html">Query Builder Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../database/transactions.html">Transactions</a></li>
<li class="toctree-l2"><a class="reference internal" href="../database/metadata.html">Getting MetaData</a></li>
<li class="toctree-l2"><a class="reference internal" href="../database/call_function.html">Custom Function Calls</a></li>
<li class="toctree-l2"><a class="reference internal" href="../database/caching.html">Query Caching</a></li>
<li class="toctree-l2"><a class="reference internal" href="../database/forge.html">Database Manipulation with Database Forge</a></li>
<li class="toctree-l2"><a class="reference internal" href="../database/utilities.html">Database Utilities Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../database/db_driver_reference.html">Database Driver Reference</a></li>
</ul>
</li>
</ul>
<ul>
<li class="toctree-l1"><a class="reference internal" href="../helpers/index.html">Helpers</a><ul>
<li class="toctree-l2"><a class="reference internal" href="../helpers/array_helper.html">Array Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/captcha_helper.html">CAPTCHA Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/cookie_helper.html">Cookie Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/date_helper.html">Date Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/directory_helper.html">Directory Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/download_helper.html">Download Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/email_helper.html">Email Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/file_helper.html">File Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/form_helper.html">Form Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/html_helper.html">HTML Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/inflector_helper.html">Inflector Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/language_helper.html">Language Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/number_helper.html">Number Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/path_helper.html">Path Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/security_helper.html">Security Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/smiley_helper.html">Smiley Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/string_helper.html">String Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/text_helper.html">Text Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/typography_helper.html">Typography Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/url_helper.html">URL Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/xml_helper.html">XML Helper</a></li>
</ul>
</li>
</ul>
</div>
</nav>
<section data-toggle="wy-nav-shift" class="wy-nav-content-wrap">
<nav class="wy-nav-top" role="navigation" aria-label="top navigation">
<i data-toggle="wy-nav-top" class="fa fa-bars"></i>
<a href="../index.html">CodeIgniter</a>
</nav>
<div class="wy-nav-content">
<div class="rst-content">
<div role="navigation" aria-label="breadcrumbs navigation">
<ul class="wy-breadcrumbs">
<li><a href="../index.html">Docs</a> »</li>
<li><a href="index.html">General Topics</a> »</li>
<li>Helper Functions</li>
<li class="wy-breadcrumbs-aside">
</li>
<div style="float:right;margin-left:5px;" id="closeMe">
<img title="Classic Layout" alt="classic layout" src="data:image/gif;base64,R0lGODlhFAAUAJEAAAAAADMzM////wAAACH5BAUUAAIALAAAAAAUABQAAAImlI+py+0PU5gRBRDM3DxbWoXis42X13USOLauUIqnlsaH/eY6UwAAOw==" />
</div>
</ul>
<hr/>
</div>
<div role="main" class="document">
<div class="section" id="helper-functions">
<h1>Helper Functions<a class="headerlink" href="#helper-functions" title="Permalink to this headline">¶</a></h1>
<p>Helpers, as the name suggests, help you with tasks. Each helper file is
simply a collection of functions in a particular category. There are <strong>URL
Helpers</strong>, that assist in creating links, there are Form Helpers that help
you create form elements, <strong>Text Helpers</strong> perform various text formatting
routines, <strong>Cookie Helpers</strong> set and read cookies, File Helpers help you
deal with files, etc.</p>
<p>Unlike most other systems in CodeIgniter, Helpers are not written in an
Object Oriented format. They are simple, procedural functions. Each
helper function performs one specific task, with no dependence on other
functions.</p>
<p>CodeIgniter does not load Helper Files by default, so the first step in
using a Helper is to load it. Once loaded, it becomes globally available
in your <a class="reference internal" href="controllers.html"><span class="doc">controller</span></a> and
<a class="reference internal" href="views.html"><span class="doc">views</span></a>.</p>
<p>Helpers are typically stored in your <strong>system/helpers</strong>, or
<strong>application/helpers directory</strong>. CodeIgniter will look first in your
<strong>application/helpers directory</strong>. If the directory does not exist or the
specified helper is not located there CI will instead look in your
global <em>system/helpers/</em> directory.</p>
<div class="section" id="loading-a-helper">
<h2>Loading a Helper<a class="headerlink" href="#loading-a-helper" title="Permalink to this headline">¶</a></h2>
<p>Loading a helper file is quite simple using the following method:</p>
<div class="highlight-ci"><div class="highlight"><pre><span></span><span class="nv">$this</span><span class="o">-></span><span class="na">load</span><span class="o">-></span><span class="na">helper</span><span class="p">(</span><span class="s1">'name'</span><span class="p">);</span>
</pre></div>
</div>
<p>Where <strong>name</strong> is the file name of the helper, without the .php file
extension or the “helper” part.</p>
<p>For example, to load the <strong>URL Helper</strong> file, which is named
<strong>url_helper.php</strong>, you would do this:</p>
<div class="highlight-ci"><div class="highlight"><pre><span></span><span class="nv">$this</span><span class="o">-></span><span class="na">load</span><span class="o">-></span><span class="na">helper</span><span class="p">(</span><span class="s1">'url'</span><span class="p">);</span>
</pre></div>
</div>
<p>A helper can be loaded anywhere within your controller methods (or
even within your View files, although that’s not a good practice), as
long as you load it before you use it. You can load your helpers in your
controller constructor so that they become available automatically in
any function, or you can load a helper in a specific function that needs
it.</p>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last">The Helper loading method above does not return a value, so
don’t try to assign it to a variable. Just use it as shown.</p>
</div>
</div>
<div class="section" id="loading-multiple-helpers">
<h2>Loading Multiple Helpers<a class="headerlink" href="#loading-multiple-helpers" title="Permalink to this headline">¶</a></h2>
<p>If you need to load more than one helper you can specify them in an
array, like this:</p>
<div class="highlight-ci"><div class="highlight"><pre><span></span><span class="nv">$this</span><span class="o">-></span><span class="na">load</span><span class="o">-></span><span class="na">helper</span><span class="p">(</span>
<span class="k">array</span><span class="p">(</span><span class="s1">'helper1'</span><span class="p">,</span> <span class="s1">'helper2'</span><span class="p">,</span> <span class="s1">'helper3'</span><span class="p">)</span>
<span class="p">);</span>
</pre></div>
</div>
</div>
<div class="section" id="auto-loading-helpers">
<h2>Auto-loading Helpers<a class="headerlink" href="#auto-loading-helpers" title="Permalink to this headline">¶</a></h2>
<p>If you find that you need a particular helper globally throughout your
application, you can tell CodeIgniter to auto-load it during system
initialization. This is done by opening the <strong>application/config/autoload.php</strong>
file and adding the helper to the autoload array.</p>
</div>
<div class="section" id="using-a-helper">
<h2>Using a Helper<a class="headerlink" href="#using-a-helper" title="Permalink to this headline">¶</a></h2>
<p>Once you’ve loaded the Helper File containing the function you intend to
use, you’ll call it the way you would a standard PHP function.</p>
<p>For example, to create a link using the <code class="docutils literal"><span class="pre">anchor()</span></code> function in one of
your view files you would do this:</p>
<div class="highlight-ci"><div class="highlight"><pre><span></span><span class="o"><?</span><span class="nx">php</span> <span class="k">echo</span> <span class="nx">anchor</span><span class="p">(</span><span class="s1">'blog/comments'</span><span class="p">,</span> <span class="s1">'Click Here'</span><span class="p">);</span><span class="cp">?></span>
</pre></div>
</div>
<p>Where “Click Here” is the name of the link, and “blog/comments” is the
URI to the controller/method you wish to link to.</p>
</div>
<div class="section" id="extending-helpers">
<h2>“Extending” Helpers<a class="headerlink" href="#extending-helpers" title="Permalink to this headline">¶</a></h2>
<p>To “extend” Helpers, create a file in your <strong>application/helpers/</strong> folder
with an identical name to the existing Helper, but prefixed with <strong>MY_</strong>
(this item is configurable. See below.).</p>
<p>If all you need to do is add some functionality to an existing helper -
perhaps add a function or two, or change how a particular helper
function operates - then it’s overkill to replace the entire helper with
your version. In this case it’s better to simply “extend” the Helper.</p>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last">The term “extend” is used loosely since Helper functions are
procedural and discrete and cannot be extended in the traditional
programmatic sense. Under the hood, this gives you the ability to
add to or or to replace the functions a Helper provides.</p>
</div>
<p>For example, to extend the native <strong>Array Helper</strong> you’ll create a file
named <strong>application/helpers/MY_array_helper.php</strong>, and add or override
functions:</p>
<div class="highlight-ci"><div class="highlight"><pre><span></span><span class="c1">// any_in_array() is not in the Array Helper, so it defines a new function</span>
<span class="k">function</span> <span class="nf">any_in_array</span><span class="p">(</span><span class="nv">$needle</span><span class="p">,</span> <span class="nv">$haystack</span><span class="p">)</span>
<span class="p">{</span>
<span class="nv">$needle</span> <span class="o">=</span> <span class="nb">is_array</span><span class="p">(</span><span class="nv">$needle</span><span class="p">)</span> <span class="o">?</span> <span class="nv">$needle</span> <span class="o">:</span> <span class="k">array</span><span class="p">(</span><span class="nv">$needle</span><span class="p">);</span>
<span class="k">foreach</span> <span class="p">(</span><span class="nv">$needle</span> <span class="k">as</span> <span class="nv">$item</span><span class="p">)</span>
<span class="p">{</span>
<span class="k">if</span> <span class="p">(</span><span class="nb">in_array</span><span class="p">(</span><span class="nv">$item</span><span class="p">,</span> <span class="nv">$haystack</span><span class="p">))</span>
<span class="p">{</span>
<span class="k">return</span> <span class="k">TRUE</span><span class="p">;</span>
<span class="p">}</span>
<span class="p">}</span>
<span class="k">return</span> <span class="k">FALSE</span><span class="p">;</span>
<span class="p">}</span>
<span class="c1">// random_element() is included in Array Helper, so it overrides the native function</span>
<span class="k">function</span> <span class="nf">random_element</span><span class="p">(</span><span class="nv">$array</span><span class="p">)</span>
<span class="p">{</span>
<span class="nb">shuffle</span><span class="p">(</span><span class="nv">$array</span><span class="p">);</span>
<span class="k">return</span> <span class="nb">array_pop</span><span class="p">(</span><span class="nv">$array</span><span class="p">);</span>
<span class="p">}</span>
</pre></div>
</div>
<div class="section" id="setting-your-own-prefix">
<h3>Setting Your Own Prefix<a class="headerlink" href="#setting-your-own-prefix" title="Permalink to this headline">¶</a></h3>
<p>The filename prefix for “extending” Helpers is the same used to extend
libraries and core classes. To set your own prefix, open your
<strong>application/config/config.php</strong> file and look for this item:</p>
<div class="highlight-ci"><div class="highlight"><pre><span></span><span class="nv">$config</span><span class="p">[</span><span class="s1">'subclass_prefix'</span><span class="p">]</span> <span class="o">=</span> <span class="s1">'MY_'</span><span class="p">;</span>
</pre></div>
</div>
<p>Please note that all native CodeIgniter libraries are prefixed with <strong>CI_</strong>
so DO NOT use that as your prefix.</p>
</div>
</div>
<div class="section" id="now-what">
<h2>Now What?<a class="headerlink" href="#now-what" title="Permalink to this headline">¶</a></h2>
<p>In the Table of Contents you’ll find a list of all the available Helper
Files. Browse each one to see what they do.</p>
</div>
</div>
</div>
<footer>
<div class="rst-footer-buttons" role="navigation" aria-label="footer navigation">
<a href="libraries.html" class="btn btn-neutral float-right" title="Using CodeIgniter Libraries">Next <span class="fa fa-arrow-circle-right"></span></a>
<a href="models.html" class="btn btn-neutral" title="Models"><span class="fa fa-arrow-circle-left"></span> Previous</a>
</div>
<hr/>
<div role="contentinfo">
<p>
© Copyright 2014 - 2018, British Columbia Institute of Technology.
Last updated on Mar 22, 2018.
</p>
</div>
Built with <a href="http://sphinx-doc.org/">Sphinx</a> using a <a href="https://github.com/snide/sphinx_rtd_theme">theme</a> provided by <a href="https://readthedocs.org">Read the Docs</a>.
</footer>
</div>
</div>
</section>
</div>
<script type="text/javascript">
var DOCUMENTATION_OPTIONS = {
URL_ROOT:'../',
VERSION:'3.1.8',
COLLAPSE_INDEX:false,
FILE_SUFFIX:'.html',
HAS_SOURCE: false
};
</script>
<script type="text/javascript" src="../_static/jquery.js"></script>
<script type="text/javascript" src="../_static/underscore.js"></script>
<script type="text/javascript" src="../_static/doctools.js"></script>
<script type="text/javascript" src="../_static/js/theme.js"></script>
<script type="text/javascript">
jQuery(function () {
SphinxRtdTheme.StickyNav.enable();
});
</script>
</body>
</html>
|
