mb_substr
- (PHP 4 >= 4.0.6, PHP 5, PHP 7)
- mb_substr — Get part of string
- mb_substr — 获取部分字符串
Description
string mb_substr ( ????string $str , ???int $start [, ???int $length = NULL [, ????string $encoding = mb_internal_encoding() ]] ????)// Performs a multi-byte safe substr() operation based on number of characters. Position is counted from // the beginning of str. First character's position is 0. Second character position is 1, and so on.//根据字符数执行一个多字节安全的 substr() 操作。 位置是从 str 的开始位置进行计数。 第一个字符的位置是 0。第二个字符的位置是 1，以此类推。Parameters
str
- The string to extract the substring from.
- 从该 string 中提取子字符串。
start
- If start is non-negative, the returned string will start at the start‘th position in str, counting from zero. For instance, in the string ‘abcdef‘, the character at position 0 is ‘a‘, the character at position 2 is ‘c‘, and so forth.
如果 start 不是负数，返回的字符串会从 str 第 start 的位置开始，从 0 开始计数。举个例子，字符串 ‘abcdef‘，位置 0 的字符是 ‘a‘，位置 2 的字符是 ‘c‘，以此类推。
- If start is negative, the returned string will start at the start‘th character from the end of str.
如果 start 是负数，返回的字符串是从 str 末尾处第 start 个字符开始的。
length
- Maximum number of characters to use from str. If omitted or NULL is passed, extract all characters to the end of the string.
- str 中要使用的最大字符数。如果省略了此参数或者传入了 NULL，则会提取到字符串的尾部。
encoding
- The encoding parameter is the character encoding. If it is omitted, the internal character encoding value will be used.
- encoding 参数为字符编码。如果省略，则使用内部字符编码。
Return Values
- mb_substr() returns the portion of str specified by the start and length parameters.
- mb_substr() 函数根据 start 和 length 参数返回 str 中指定的部分。
Changelog
- 5.4.8 - Passing NULL as length extracts all characters to the end of the string. Prior to this version NULL was treated the same as 0.
Examples
<?php/** * Created by PhpStorm. * User: zhangrongxiang * Date: 2018/1/30 * Time: 下午8:51 */$string = "0123456789你好";/** start > 0 ?length > 0*/$mystring = mb_substr( $string, 5, 1 );echo $mystring . PHP_EOL; // 5$mystring = mb_substr( $string, 5, 2 );echo $mystring . PHP_EOL; // 56$mystring = mb_substr( $string, 10, 2 );echo $mystring . PHP_EOL; // 你好/** start < 0 ?length > 0*/$mystring = mb_substr( $string, - 2, 2 );echo $mystring . PHP_EOL; // 你好echo 'mb_strlen : ' . mb_strlen( $string ) . PHP_EOL;//12$mystring = mb_substr( $string, - mb_strlen( $string ), 2 );echo $mystring . PHP_EOL; // 01$mystring = mb_substr( $string, - 3, 2 );echo $mystring . PHP_EOL; // 9你/** start > 0 ?length < ?0*/$mystring = mb_substr( $string, 5, - 1 );echo $mystring . PHP_EOL; // 56789你$mystring = mb_substr( $string, 0, - mb_strlen( $string ) + 1 );echo $mystring . PHP_EOL; // 0$mystring = mb_substr( $string, 5, - 5 );echo $mystring . PHP_EOL; // 56/** start < 0 ?length < ?0*/$mystring = mb_substr( $string, - 10, - 1 );echo $mystring . PHP_EOL; // 23456789你$mystring = mb_substr( $string, - 5, - 1 );echo $mystring . PHP_EOL; // 789你function mb_ucfirst( $str, $enc = 'utf-8' ) { ???return mb_strtoupper( mb_substr( $str, 0, 1, $enc ), $enc ) . mb_substr( $str, 1, mb_strlen( $str, $enc ), $enc );}echo mb_ucfirst( "hello world 你好 中国" ) . PHP_EOL; //Hello world 你好 中国/** * @param $string * @param string $encoding * * @return array */function get_character_classes( $string, $encoding = "UTF-8" ) { ???$current_encoding = mb_internal_encoding(); ???mb_internal_encoding( $encoding ); ???$has ?????????= array(); ???$stringlength = mb_strlen( $string, $encoding ); ???for ( $i = 0; $i < $stringlength; $i ++ ) { ???????$c = mb_substr( $string, $i, 1 ); ???????if ( ( $c >= "0" ) && ( $c <= "9" ) ) { ???????????$has['numeric'] = "numeric"; ???????} else if ( ( $c >= "a" ) && ( $c <= "z" ) ) { ???????????$has['alpha'] ?????= "alpha"; ???????????$has['alphalower'] = 'alphalower'; ???????} else if ( ( $c >= "A" ) && ( $c <= "Z" ) ) { ???????????$has['alpha'] ?????= "alpha"; ???????????$has['alphaupper'] = "alphaupper"; ???????} else if ( ( $c == "$" ) || ( $c == "￡" ) ) { ???????????$has['currency'] = "currency"; ???????} else if ( ( $c == "." ) && ( $has['decimal'] ) ) { ???????????$has['decimals'] = "decimals"; ???????} else if ( $c == "." ) { ???????????$has['decimal'] = "decimal"; ???????} else if ( $c == "," ) { ???????????$has['comma'] = "comma"; ???????} else if ( $c == "-" ) { ???????????$has['dash'] = "dash"; ???????} else if ( $c == " " ) { ???????????$has['space'] = "space"; ???????} else if ( $c == "/" ) { ???????????$has['slash'] = "slash"; ???????} else if ( $c == ":" ) { ???????????$has['colon'] = "colon"; ???????} else if ( ( $c >= " " ) && ( $c <= "~" ) ) { ???????????$has['ascii'] = "ascii"; ???????} else { ???????????$has['binary'] = "binary"; ???????} ???} ???mb_internal_encoding( $current_encoding ); ???????return $has;}$string = "1234asdfA￡^_{}|}~????";foreach ( get_character_classes( $string ) as $k => $v ) { ???echo $k . " : " . $v . PHP_EOL;}//numeric : numeric//alpha : alpha//alphalower : alphalower//alphaupper : alphaupper//currency : currency//ascii : ascii//binary : binary文章参考
http://php.net/manual/en/function.mb-substr.php
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