Tutorial on extracting numbers from string in php

Strings are what we programmers must come into contact with legal persons. Sometimes we need to extract all the numbers from a string at work. In fact, there are quite a lot of research on this method. How to use PHP to extract the numbers in a string? We have made a small summary of the functions of number extraction and would like to share it with you. The three methods are summarized as follows:

The first method uses regular expressions:

function findNum($str=''){
$str=trim($str);
if(empty($str)){return '';}
$reg='/(\d{3}(\.\d+)?)/is';//匹配数字的正则表达式
preg_match_all($reg,$str,$result);
if(is_array($result)&&!empty($result)&&!empty($result[1])&&!empty($result[1][0])){
return $result[1][0];
}
return '';
}

The second method Method, use the in_array method:

function findNum($str=''){
$str=trim($str);
if(empty($str)){return '';}
$temp=array('1','2','3','4','5','6','7','8','9','0');
$result='';
for($i=0;$i<strlen($str);$i++){
if(in_array($str[$i],$temp)){
$result.=$str[$i];
}
}
return $result;
}

The third method, use the is_numeric function:

function findNum($str=''){
$str=trim($str);
if(empty($str)){return '';}
$result='';
for($i=0;$i<strlen($str);$i++){
if(is_numeric($str[$i])){
$result.=$str[$i];
}
}
return $result;
}

The above three methods are all methods of extracting numbers in strings using PHP. You can Choose the one that suits you best.

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