A brief analysis of whether 0 is true or false in php

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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