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A brief analysis of whether 0 is true or false in php
- PHPzOriginal
- 2023-04-06 09:15:112531browse
In PHP language, 0 can be either true or false, depending on the context.
First of all, it should be clear that the Boolean type in PHP has only two values: true and false. In logical operations, 0 represents false and 1 represents true. In PHP, 0 is also used as a numeric type.
When 0 is judged as a Boolean type, 0 is considered false. This means that the judgment statements in the following code block will all return false:
if (0) {
// 不会执行
}
if (false) {
// 不会执行
}
if ('') {
// 不会执行
}
However, in some cases, 0 will be considered true. If 0 is compared to a string (e.g. "0" == 0), 0 will be converted to string type, in which case 0 will be treated as true. For example:
if ("0") {
// 这里会执行，因为"0"被当作true
}
In addition, when the return value needs to be converted to a Boolean type, 0 is no longer considered false, but is considered true. For example:
function returnTrue() {
return 0;
}
if (returnTrue()) {
// 这里会执行，因为returnTrue()返回的是0，被当作true
}
It should be noted that although 0 can be considered true, rigorous code design should avoid confusion. It is better to use clear true and false values to avoid unexpected errors.
To summarize, 0 in PHP can be considered either true or false, depending on the context. Rigorous code design should avoid confusion, and it is wiser to use clear true and false values.
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