PHP and JavaScript convert strings to digital String2int

When I looked at Liaoche's JavaScript tutorial, there was a problem in that using reduce () to convert a string to int, I looked at the method posted in the comments, it was quite an accident, thought he only used a line of code, that is, the following line of code

var str= "123456"; var num=str*1;

Because JavaScript and PHP are both weakly typed languages, the same variable name can be repeatedly assigned different types of values, and then I try it again with PHP, as expected.

<?php$str= "123456"; $num = $str *1;var_dump ($num);//int (123456)?>

Have to say, this method is indeed very innovative, the same method, but also can use s-0,s+0, etc.

PHP and JavaScript convert strings to digital String2int