bool和 == 运算的有关问题

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Beware of certain control behavior with boolean and non boolean values :<br />
<br />
<?php<br />
// Consider that the 0 could by any parameters including itself<br />
var_dump(0 == 1); // false<br />
var_dump(0 == (bool)'all'); // false<br />
var_dump(0 == 'all'); // TRUE, take care<br />
var_dump(0 === 'all'); // false<br />
<br />
// To avoid this behavior, you need to cast your parameter as string like that :<br />
var_dump((string)0 == 'all'); // false<br />
?> <br />