preg_match decimals not working

问题

I seem to be having a problem with a preg_match code, I am trying to get the decimal number from a string which should be something like '3.25' but instead I get '1'

preg_match('/[0-9]+(?:\.[0-9]*)?/', '£3.25', $matches);
echo 'match: '.$matches[0];

prints "1"

回答1:

preg_match('#\d+(?:\.\d{1,2})?#', '£2.35', $match);
var_dump($match);

gives

array(1) {
  [0]=>
  string(4) "2.35"
}

even on PHP 5.2 : http://codepad.viper-7.com/9nFhET

回答2:

First, you'll find the value at the index 1 of the array ( $matches[1] )

Try something like that :

<?php
preg_match('/[0-9]+\.([0-9]+)/', '£3.25', $matches);
print_r($matches);
?>

That gives :

Array
(
    [0] => £3.25
    [1] => 25
)

回答3:

I can repro an issue with decimals on this tester site:
http://www.pagecolumn.com/tool/pregtest.htm

If you replace the escaped dot with a character class that contains a dot it works:

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

Btw: is it possible that you get the dot but no digits after it ?
If not I would replace the [0-9]* with either [0-9]+ or a specific number of digits expected [0-9]{2}

来源：https://stackoverflow.com/questions/10371476/preg-match-decimals-not-working