is_numeric() 与 is_float() 与 is_int() [英] is_numeric() vs. is_float() vs. is_int()

问题描述

我的理解是...

if is_numeric($input) === true

然后要么

is_float($input) === true 或

is_int($input) === true 或

$input === 0 或

$input 是一个数字字符串(意味着如果它没有用引号括起来，它将满足前 3 个之一).

$input is a numeric string (meaning it'd satisfy one of the first 3 if it weren't wrapped in quotes).

准确吗?还有其他区别吗?

Is that accurate? Are there other differences?

推荐答案

查看 PHP 关于 is_numeric.它讨论了允许的所有内容，而且不仅仅是 is_float 和 is_int.

See PHP's documentation on is_numeric. It talks about everything that is allowed, and it's more than is_float and is_int.

同样重要的是要注意 is_int 仅适用于整数类型的事物，这意味着不允许使用字符串表示.这是验证表单输入是否为整数时的常见问题.您应该将 filter_var 或过滤器系列中的某些内容与过滤器 FILTER_VALIDATE_INT 一起使用.对于浮点数，请使用 FILTER_VALIDATE_FLOAT.

It's also important to note that is_int only works on things that are type integer, meaning string representations are not allowed. This is a common problem when verifying that form input is an integer. You should use filter_var or something from the filter family with the filter FILTER_VALIDATE_INT. For floats, use FILTER_VALIDATE_FLOAT.

此外，如果您尝试检查整数的原因是将参数验证为整数，那么在 PHP 7 中您可以这样做:

Also, if the reason you are trying to check for an integer is to validate a parameter as being an int, then in PHP 7 you can do this:

function foo(int $i) {
    // $i is guaranteed to be an int (is_int) will be true
}

PHP 7 有两种不同的转换为 int 的模式；这个答案对其进行了更多解释.

PHP 7 has two different modes for converting to int; this answer explains it a bit more.

请注意，如果您正在验证表单元素的内容，这可能不是您想要的.使用 filter_var 解决方案.

Note that this is probably not what you want if you are validating the contents of a form element. Use the filter_var solution for that.

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