<?php
$mobile = "15810320826";
echo substr_replace($mobile,'****',3 , 4); //将手机号中间4位隐藏为*号,结果为158****0826
?>
<?php
$time=1591457255;
echo substr_replace($time,"#",4,1); //将时间戳第4位替换为#,结果为159#457255
?>
<?php
$mobile = "15810320826";
echo substr_replace($mobile,'****',3 , 4); //将手机号中间4位隐藏为*号,结果为158****0826
?>
<?php
$time=1591457255;
echo substr_replace($time,"#",4,1); //将时间戳第4位替换为#,结果为159#457255
?>