Everyone knows that there are functions substr and substring for string interception in js. What about php? PHP does not have a directly available substring function, but there is a substr function.
If you don’t believe it, you can test it yourself. A correct piece of code is given below.
<?$a="me";echo(substr($a,,));//输出me?>下面又给出一段错误的代码<?$a="me";echo(subString($a,,));?> substr() 函数返回字符串的一部分。 substr(string,start,length) string:要截取的字符串
start:
Positive number - starts at the specified position in the string
Negative number - starts at the specified position from the end of the string
0 - starts at the specified position in the string Starts at one character
length:
Optional. Specifies the length of the string to be returned. The default is until the end of the string.
Positive number - Return from the position of the start parameter
Negative number - Return from the end of the string
Detailed explanation of the usage of PHP substr()
Definition and usage
## The #substr() function returns a portion of a string. Using the substr() function to intercept Chinese may cause garbled characters. It is recommended to use the mb_substr() function to intercept Chinese. Syntaxsubstr(string,start,length)Parameters
<?php $str = 'hello world!'; echo substr($str, 4); // o world! 左起第4开始向右截取到末尾 echo substr($str, 4, 5); // o wor 左起第4开始向右取5位 echo substr($str, 4, -1); // o world 左起第4与右起第1之间的字符 echo substr($str, -8, 4); // o wo 右起第8开始向右截取4位 echo substr($str, -8,-2); // o worl 右起第8与右起第2之间的字符There are many questions about the PHPsubstr function. If netizens still have such questions, you can pay attention to the PHP Chinese website. We will provide a large number of technical articles to answer your questions.Related recommendations:
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The above is the detailed content of Correct usage of substr and substring in PHP. For more information, please follow other related articles on the PHP Chinese website!

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