如何检查值是否为 javascript 中的浮点数
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How can I check to see if a value is a float in javascript
提问by Dennis Martinez
I want to check to see if my input is a float.
我想检查一下我的输入是否是浮点数。
Sooo something like...
Sooo之类的...
if (typeof (input) == "float")
do something....
What is the proper way to do this?
这样做的正确方法是什么？
回答by naveen
Try parseFloat
尝试 parseFloat
The parseFloat()function parses an argument (converting it to a string first if needed) and returns a floating point number.
所述parseFloat（）函数解析参数（其转换为第一，如果需要的字符串），并返回一个浮点数。
if(!isNaN(parseFloat(input))) {
// is float
}
回答by spraff
All numbers are floats in Javascript. Note that the type name is in quotes, it's a string, and it's all lower case. Also note that typeofis an operator, not a function, no need for parens (though they're harmless).
所有数字都是 Javascript 中的浮点数。请注意，类型名称在引号中，它是一个字符串，并且都是小写的。另请注意，这typeof是一个运算符，而不是一个函数，不需要括号（尽管它们是无害的）。
回答by T.J. Crowder
As spraff said, you can check the type of an input with typeof. In this case
正如 spraff 所说，您可以使用typeof. 在这种情况下
if (typeof input === "number") {
// It's a number
}
JavaScript just has Number, not separate floatand integertypes. More about figuring out what things are in JavaScript: Say what?
JavaScript 只有Number，而不是单独的float和integer类型。更多关于弄清楚 JavaScript 中的内容：说什么？
If it may be something else (like a string) but you want to convert it to a number if possible, you can use either Numberor parseFloat:
如果它可能是其他东西（如字符串）但您想尽可能将其转换为数字，则可以使用Number或parseFloat：
input = Number(input);
if (!isNaN(input)) {
// It was already a number or we were able to convert it
}
More:
更多的：
