为什么php数组的整数键变为负数（<0）？

Question

var_dump(array_filter(array(4294967295 => 22)));

The result:

array(1) {  
    [-1] =>  
    int(22)
}

Why the key is < 0 ?

Answer 1

Max size of intare as follows:-

32-bit builds of PHP:

Integers can be from -2147483648 to 2147483647

64-bit builds of PHP:

Integers can be from -9223372036854775808 to 9223372036854775807

It seems you are using 32 bit builds and that's why you are getting that problem.