如何将混合的PHP字符串转换为仅数字

I have a string like this:

$string = 'e.g. 25.32';

I want to pull out only the number (25.32)

The text surrounding the number could potentially be any non-number.

You could use regular expressions if you know the format of your string with preg_match

You could use something like :

<?php
     $str = "e.g. 25";
     $val = (int)$str;
?>

But it's not the best solution.

A "stronger" and universal alternative is...

Code : (UPDATED)

<?php
    $str = "e.g. 25.32";

    preg_match("/([0-9]+[\.,]?)+/",$str,$matches);

    $val = $matches[0];

    echo $val;
?>

Output :

25.32

As a function : (UPDATED)

<?php
      function getInt($str)
      {
            preg_match("/([0-9]+[\.,]?)+/",$str,$matches);
            return $matches[0];
      }
?>

Usage :

<?php
      $val = getInt("e.g. 25.32");
?>

My old function that also works with negative numbers:

function getNumber($str){
    return floatval(preg_replace('/^[^\d-]+/','',$str));
}

If the number is simple:

([0-9]+(?:\.[0-9]+)?)

You then want to match this at the end of the string:

$string = 'e.g. 25.32';
$number = preg_replace('~^.*?([0-9]+(?:\.[0-9]+)?)$~', '$1', $string);

This will make $number contain "25.32", convert it to float if you need the float value:

$float = (float) $number;

This code does only work if there actually is a number. If you can't be sure it is, test first:

$string = 'e.g. 25.32';
$number = NULL;
$hasNumber = preg_match('~([0-9]+(?:\.[0-9]+)?)$~', $string, $matches);
if ($hasNumber)
{
    list(, $number) = $matches;
}

If the number can be a number as in PHP:

([+-]?INF|[+-]?(([0-9]+|([0-9]*[\.][0-9]+)|([0-9]+[\.][0-9]*))|([0-9]+|(([0-9]*[\.][0-9]+)|([0-9]+[\.][0-9]*)))[eE][+-]?[0-9]+))

So take care what you actually need to match.