PHP：获取字符串的子字符串从'％'开始到第3次出现

I got a different strings with lists of percentages:

'51% 20% 19% 6% 3% 2% 2% ...'

How can I cut the string to:

'51% 20% 19%'

Maybe some regex?

You could match up until the 3rd occurrence of the percent sign.

$str = '51% 20% 19% 6% 3% 2% 2%';
preg_match('/^(?:[^%]*%){3}/', $str, $match);
echo $match[0];                 //=> "51% 20% 19%"

A verbose way would be..

$str = '51% 20% 19% 6% 3% 2% 2%';
$val = explode(' ', $str);
echo "$val[0] $val[1] $val[2]"; //=> "51% 20% 19%"