- var_dump: documentation ( source)
- preg_match: documentation ( source)
<?php
$key = '价格';
$doc = [];
$doc[$key] = "0";
$value = $doc[$key];
var_dump($doc);
if(preg_match('/[0-9]\d*/', $value)) $doc[$key] = floatval($value);
else unset($doc[$key]);
var_dump($doc);