php method to extract the first few digits of a string: You can use the substr() function to extract. This function can return the extracted part of the string, return false if it fails, or return an empty string, such as [substr($str, 0, 3);].
The substr() function returns the extracted portion of the string, FALSE if failed, or an empty string.
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Syntax:
substr(string,start,length)
Parameters:
string Required. Specifies a part of the string to be returned.
start Required. Specifies where in the string to begin.
length Optional. Specifies the length of the string to be returned. The default is until the end of the string.
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Implementation code:
<?php $str = "123456789"; echo substr($str , 0 , 3);//从左边第一位字符起截取3位字符:结果:123 echo substr($str , 3 , 3);//从左边第3位字符起截取3位字符:结果:456 ?>
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