function extract($arr,$prefix) {
		$out=[];
		foreach (preg_grep('/^'.preg_quote($prefix,'/').'/',array_keys($arr))
			as $key)
			$out[substr($key,strlen($prefix))]=$arr[$key];
		return $out;
	}
function extract($arr,$prefix) {
		$out=[];
		foreach (preg_grep('/^'.preg_quote($prefix,'/').'/',array_keys($arr))
			as $key)
			$out[substr($key,strlen($prefix))]=$arr[$key];
		return $out;
	}
function extract ( $ arr , $ prefix ) { $ out = [ ] ; foreach ( preg_grep ( '/^' . preg_quote ( $ prefix , '/' ) . '/' , array_keys ( $ arr ) ) as $ key ) $ out [ substr ( $ key , strlen ( $ prefix ) ) ] = $ arr [ $ key ] ; return $ out ; }
Extract values of array whose keys start with the given prefix
@return array
@param $arr array
@param $prefix string
Extract values of array whose keys start with the given prefix