PHP character-to-integer

1 $arr Array (0=>1, "AA" =>2, 3, 4); 2  3 foreach ($arras$key= +$val) {4     Print ($key$val); 5 }

Output results: 5534

Why

When two values in PHP are logically judged, if the type of two values is inconsistent PHP automatically converts the value on the right to the left type.

And then make a judgment. So the "AA" transformation is equal to 0, and naturally equals the left 0.

Character-type conversion shaping

Example:

Var_dump ((int) (' B '));                     // 0    Var_dump ((int) (' very good '));       // 0    Var_dump ((int) (' 132very '));             //  the    Var_dump ((int) (' ver1323 '));            // 0

You can draw a rule: start with a valid number and go to a valid number. Convert to 0, starting with a non-valid number;

PHP character-to-integer