How to use Iconv function in PHP

Source: Internet
Author: User
Tags php programming translit
The content of this article is introduced in PHP iconv function of the use of the method, here to share to you, the need for friends can refer to

Recently in a program, you need to use the ICONV function to fetch the UTF-8 encoded page into gb2312, found that only with the ICONV function to fetch the data of a transcoding data will be less for no reason.

Iconv function Library can complete the conversion between various character sets, which is an indispensable base Function library in PHP programming.
1, download Libiconv function library;
2, decompression TAR-ZXVF libiconv-1.9.2.tar.gz;
3, Installation Libiconv
#make Install
4. Recompile php add compiler parameter--with-iconv=/usr/local/iconv

Windows under

Recently in a thief program, need to use the ICONV function to fetch the UTF-8 encoded page into gb2312, found that only with the ICONV function to fetch the data of a transcoding data will be less for no reason. Let me depressed for a while, go online a check information to know this is a iconv function of a bug. Iconv error when converting character "-" to gb2312
The workaround is simply to add "//ignore" to the second parameter of the ICONV function after the code that needs to be converted.

The following is the referenced content:

Copy the Code code as follows:

Iconv ("UTF-8", "Gb2312//ignore", $data)

Ignore means ignoring errors at the time of conversion, and if there is no ignore argument, all strings after that character cannot be saved.

Copy the Code code as follows:

<?php echo $str = ' Hello, here is coffee! '; echo ' <br/> '; echo iconv (' GB2312 ', ' UTF-8 ', $str); Transfer the encoding of the string from GB2312 to UTF-8 Echo ' <br/> '; Echo Iconv_substr ($STR, 1, 1, ' UTF-8 '); Intercept by the number of characters rather than byte Print_r (iconv_get_encoding ()); Get the current page encoding information echo iconv_strlen ($str, ' UTF-8 '); Get the string length of the set encoding//There are also $content = Iconv ("UTF-8", "Gbk//translit", $content);?>

Iconv is not the default function for PHP, it is also the default installed module. Need to be installed to use.
If it is windows2000+php, you can modify the php.ini file, will extension=php_iconv.dll before the ";" Remove, while you copy your original PHP installation file under the Iconv.dll to your winnt/system32 (if your DLL is pointing to this directory)
In the Linux environment, the static installation of the way, in the configure when adding a--with-iconv on it, phpinfo see iconv items. (linux7.3+apache4.06+php4.3.2),

#tar ZXVF lib*
#make Install
Compiling PHP
Simple examples of use:

<?php Echo iconv ("gb2312", "iso-8859-1", "we");?>

Introduction to Mb_convert_encoding and ICONV functions in PHP

Mb_convert_encoding This function is used to convert the encoding. It turns out that the concept of program coding is not understood, but it seems to be a bit enlightened now.
However, there is generally no coding problem in English, only the Chinese data will have this problem. For example, when you write a program with Zend Studio or editplus, using GBK encoding, if the data needs to enter the database, and the database encoding is UTF8, then the data will be encoded conversion, or into the database will become garbled.

Mb_convert_encoding's usage is in the official view:

Make a GBK to UTF-8

< PHP header ("content-type:text/html; Charset=utf-8 "); Echo mb_convert_encoding ("You Are my Friend", "UTF-8", "GBK");?>

One more GB2312 to Big5.

< PHP header ("content-type:text/html; Charset=big5 "); Echo mb_convert_encoding ("You Are my Friend", "Big5", "GB2312");?>

However, to use the above function requires installation but first enable the mbstring extension library.

Another function in PHP, Iconv, is also used to convert string encodings, similar to functions on the upper function.

Here are a few more examples:

Iconv-convert string to requested character encoding (PHP 4 >= 4.0.5, PHP 5) mb_convert_encoding-convert character Encoding (PHP 4 >= 4.0.6, PHP 5)

String mb_convert_encoding (String str, string to_encoding [, mixed from_encoding])
Need to enable Mbstring expansion Library, in php.ini; Extension=php_mbstring.dll in front of; Remove
Mb_convert_encoding can specify a variety of input encoding, it will automatically identify according to the content, but the execution efficiency is much worse than the iconv;

String Iconv (String in_charset, String out_charset, String str)
Note: The second parameter, in addition to specifying the encoding to be converted to, can also add two suffixes://translit and//ignore, where//translit automatically converts characters that cannot be converted directly into one or more approximate characters,//ignore Characters that cannot be converted are ignored, and the default effect is truncated from the first illegal character.
Returns the converted string or FALSE on failure.


The iconv is found to have an error converting the character "-" to gb2312, and if there is no ignore parameter, all strings after that character cannot be saved. In any case, this "-" can not be converted successfully, unable to output. Another mb_convert_encoding does not have this bug.

In general, with Iconv, only use the Mb_convert_encoding function if you encounter an inability to determine what encoding the original encoding is, or if the Iconv conversion fails to display properly.

From_encoding is specified by character code name before conversion. It can be array or STRING-COMMA separated enumerated list. If It is not specified, the internal encoding would be used.
/* Auto detect encoding from JIS, Eucjp-win, Sjis-win, then convert str to Ucs-2le */
$str = mb_convert_encoding ($str, "Ucs-2le", "JIS, Eucjp-win, Sjis-win");
/* "Auto" is expanded to "ascii,jis,utf-8,euc-jp,sjis" */
$str = mb_convert_encoding ($str, "EUC-JP", "Auto");


$content = Iconv ("GBK", "Utf-8″, $content); $content = mb_convert_encoding ($content, "Utf-8″," GBK ");

parameters that are easy to ignore when using the Iconv function in PHP
when handling fetch content today, when using Iconv for encoding conversion, we find that the result will be interrupted, guess is the problem of character set, and consider how to skip the character that the target character set does not exist. , check the manual found Iconv function only three parameters, as if not, and then check online someone said can, but very strange how to achieve, finally found that the English description can be added to the target code behind: "Translit", very depressed how to add it? The original is to add "//", really depressed, there is such a design
Prototype: $txtContent = Iconv ("Utf-8", ' GBK ', $txtContent);

Special Parameters: Iconv ("UTF-8", "Gb2312//ignore", $data)

Two optional auxiliary parameters: Translit and IGNORE, where IGNORE means that it is skipped if it encounters an inability to convert )。 Description

String Iconv (String in_charset, String out_charset, String str)

Performs a character set conversion on the string str from In_charset to Out_charset. Returns the converted string or FALSE on failure.

If you append the string//translit to Out_charset transliteration is activated. This means if a character can ' t is represented in the target charset, it can be approximated through one or several Similarly looking characters. If you append the string//ignore, characters that cannot is represented in the target charset is silently discarded. Otherwise, str is cut from the first illegal character.

Related recommendations:

Php method for converting strings from GBK to UTF8 character set via Iconv

Phpiconv function

PHP gets mixed words in English and Chinese Iconv_strlen

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