SUBSTR (), Mb_substr () and mb_strcut function usage and differences _php tutorial

in PHP substr (), Mb_substr () and mb_strcut three functions are character interception function, but substr intercept Chinese will be garbled, and then both support Chinese interception, let me introduce.

SUBSTR () function

SUBSTR (String,start,length)

String represents the object to intercept, start indicates where to start the interception, 0 means start from the beginning, positive numbers are truncated from the position of the number, negative numbers indicate the position from the end of the intercept, but still from left to right, Length indicates how long to intercept. A negative number indicates how many characters are excluded or ignored. For example:

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$siteurl = ' www.bKjia.c0m '; Print_r (substr ($siteurl, 4)); exit;

Returns: Bkjia.c0m represents the start of the 4th character from the beginning and returns all subsequent characters.

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$siteurl = ' www.bKjia.c0m '; Print_r (substr ($siteurl, -6,2)); exit;

If you want to intercept double-byte characters. Use PHP mb_substr function or Mb_strcut function, but these two functions depend on PHP extension Php_mbstring.dll component, so configure your server. That is, the PHP installation directory of the PHP_ The Mbstring.dll file is copied to the Windows/system32 directory of your Windows 2003 C drive.

As an example:

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Echo mb_substr (' This way my string will not have garbled ^_^ ', 0, 7, ' utf-8 '); ?>

Output: so that my word

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Echo mb_strcut (' This way my string will not have garbled ^_^ ', 0, 7, ' utf-8 '); ?>

Output: Such a

As can be seen from the above example, MB_SUBSTR is the word to divide the characters, and mb_strcut is to divide the characters by Byte, but will not produce a half-character phenomenon ...

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echo Mb_substr (' Flying House blog Feihuayuan ', 0,9); Back to: Flying court echo Mb_substr (' Flying House blog Feihuayuan ', 0,9, ' utf-8 '); Then return: Flying Academy Blog Feih Mb_strcut (' Flying House blog Feihuayuan ', 0,9, ' utf-8 '); Then return to: Flying yard ?>

For example, there is a piece of text that uses MB_SUBSTR and mb_strcut to do the slicing:

PLAIN TEXT
CODE:

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$str = ' I am a long string of Chinese-'; echo "MB_SUBSTR:". Mb_substr ($str, 0, 6, ' utf-8 '); echo " "; echo "Mb_strcut:". Mb_strcut ($str, 0, 6, ' utf-8 '); ?>

The output results are as follows:

MB_SUBSTR: I'm a bunch of comparisons
Mb_strcut: I am

This article summarizes

From the above example can be seen, substr only support single-byte, so only for the English interception, and the MB_SUBSTR function is a double-font interception, just can be used in Chinese, and Mb_strcut is three bytes.

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