php is_numeric() 与 is_float() 与 is_int()
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is_numeric() vs. is_float() vs. is_int()
提问by ryanve
My understanding is...
我的理解是...
if is_numeric($input) === true
如果 is_numeric($input) === true
then either
那么要么
is_float($input) === trueOR
is_float($input) === true或者
is_int($input) === trueOR
is_int($input) === true或者
$input === 0OR
$input === 0或者
$inputis a numeric string (meaning it'd satisfy one of the first 3 if it weren't wrapped in quotes).
$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）。
Is that accurate? Are there other differences?
那是准确的吗？还有其他区别吗？
回答by Levi Morrison
See PHP's documentation on is_numeric. It talks about everything that is allowed, and it's more than is_floatand is_int.
请参阅有关is_numeric 的PHP 文档。它讨论了允许的所有内容，而且不仅仅是is_float和is_int。
It's also important to note that is_intonly 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_varor something from the filter family with the filter FILTER_VALIDATE_INT. For floats, use FILTER_VALIDATE_FLOAT.
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filter_var将过滤器系列中的或某些东西与过滤器一起使用FILTER_VALIDATE_INT。对于浮点数，请使用FILTER_VALIDATE_FLOAT.
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:
此外，如果您尝试检查整数的原因是将参数验证为 int，那么在 PHP 7 中您可以这样做：
function foo(int $i) {
// $i is guaranteed to be an int (is_int) will be true
}
PHP 7 has two different modes for converting to int; this answerexplains it a bit more.
PHP 7 有两种不同的转换为 int 的模式；这个答案解释了更多。
Note that this is probably not what you want if you are validating the contents of a form element. Use the filter_varsolution for that.
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。filter_var为此使用解决方案。
