Why is 1 == '1,2' true?

Question

Just curious how PHP type casting work for this case.

var_dump(1 == '1,2') // boolean(true)

Answer 1

That is because 1 is an integer here and when it is compared to a string 1,2 , this string will be casted to an integer , which returns 1.

How does casting a string 1,2 return 1 ?

echo int('1,2'); // prints 1 

So when it is compared to your 1 , this will be obviously returning true on your var_dump

From the PHP Docs.. (Basic Comparison Test)

If you compare a number with a string or the comparison involves numerical strings, then each string is converted to a number and the comparison performed numerically.

Source

Answer 2

1. It's interpreted as:

   var_dump(1 === (int) '1,2');
   

2. "1,2" casted to int will return 1, as anything after last parsed digit is being cutted off (,2 in this case).

3. Remember that comma (,) is not a decimal point separator, dot (.) is:

   var_dump((float) '1,3', (float) '1.3');
   

   Results in:

   (float) 1
   (float) 1.3
   

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Casting can be often very unintuitive, that's why you should almost always use === operator, which doesn't create casts.

Answer 3

If you use ==, php will type cast the right side value to the left side value. In this case '1,2' will be type cast to 1 and return true.

Even var_dump( 1== "1dfuiekjdfdsfdsfdsfdsfsdfasfsadf" ); will return true.