为什么分配和返回的结果不同？

Question

Result of assign of variable is differrent from return of a function:

function test() {
return !true
    or !true
    or !count(4)
    or (
        new stdClass() and true
    );
}

$result = !true
        or !true
        or !count(4)
        or (
            new stdClass() and true
        );

echo (int)$result . PHP_EOL; // 0

echo (int)test() . PHP_EOL; // 1

Answer 1

This is due to the Operator Precedence .

Assignment operation has higher Precedence than and / or .

First one is equal to:

function test() {
return (!true
    or !true
    or !count(4)
    or (
        new stdClass() and true
    ));
}

while second one is equal to:

($result = !true)
        or !true
        or !count(4)
        or (
            new stdClass() and true
        );

Using && / || instead of and / or , then the result will be same.