php is not equal to and is not equal,equal to

Question

I keep seeing variations of this:

Not equal !=

Not equal, equal

!==

Which one is the standard or do they have different meanings?

I am guessing the latter also checks the value and the name if it's a string, while the former might just check the value only...

Answer 1

== and != check equality by value, and in PHP you can compare different types in which certain values are said to be equivalent.

For example, "" == 0 evaluates to true, even though one is a string and the other an integer.

=== and !== check the type as well as the value.

So, "" === 0 will evaluate to false.

---

Edit: To add another example of how this "type-juggling" may catch you out, try this:

var_dump("123abc" == 123);

Gives bool(true)!