Type casting and Comparison with Loose Operator “==”

Question

I have a problem baffling me terribly. I noticed this before but didn\'t give it any heed until today. I was trying to write my own check for integer strings. I know of

Answer 1

You made an error with your post, the correct output is this:

bool(true)
bool(true)
int(0)
string(6) "string"

What happens is this:

1. Because you cast the variable to an integer, and you compare it to an integer with a loose comparison ==, PHP will first implicitely cast the string to an integer, a more explicit but 100% equivalent form would be: if((int)$var1 == (int) $var1)
2. See 1), the same thing applies here
3. It prints int(0), as it should, because it fails to parse the number, it will return 0 instead.
4. Prints string(6) "string" - as expected