银行卡号每4位加空格，13到16位用*表示(PHP)

1、调用

$this->strreplace('1111111111111');

2、执行方法 

public function strreplace($str, $startlen = 12, $endlen = 3) {
	$repstr = "";
	if (strlen($str) < ($startlen + $endlen + 1)) {
		return $str;
	}
	$count = strlen($str) - $startlen - $endlen;
	for ($i = 0; $i < $count; $i++) {
		$repstr .= "*";
	}
	$str = preg_replace('/(\d{' . $startlen . '})\d+(\d{' . $endlen . '})/', '${1}' . $repstr . '${2}', $str);
	$ns = [4, 9, 14, 19];
	for ($i = 0; $i < 4; $i++) {
		$str = $this->str_insert($str, $ns[$i], ' ');
	}
	return $str;
}

3、字符中插入字符串方法 

public function str_insert($str, $i, $substr) {
	$startstr = '';
	$laststr = '';
	for ($j = 0; $j < $i; $j++) {
		$startstr .= $str[$j];
	}
	for ($j = $i; $j < strlen($str); $j++) {
		$laststr .= $str[$j];
	}
	$str = ($startstr . $substr . $laststr);
	return $str;
}