Javascript regex to allow negative numbers

Question

I am using this regex to allow floating point numbers

str.replace(/(\.\d\d)\d+|([\d.]*)[^\d.]/, '$1$2')

I need to allow negative numbers also. Any ideas.

This allows 123.45 and it wont allow the chars like 123.45a. I need to allow -123.45. Currently its not allowing me to enter negative numbers

Answer 1

Here is a shorter regex that matches negative floats:

/^-?[0-9]\d*(\.\d+)?$/

Explaination and demo of this regex

If you want to match explicitly positive numbers like +123.123 along with the negative ones, use the following regex:

/^[-+]?[0-9]\d*(\.\d+)?$/

Source

Answer 2

Use this regex:

(?!=\A|\s)(-|)[\d^]*\.[\d]*(?=\s|\z)

It will match all floating point numbers. Demo: https://regex101.com/r/lE3gV5/2

Answer 3

You can try this Regex:

parseFloat(str.replace(/.*?(\-?)(\d*\.\d+)[^\d\.]*/, '$1$2'));

But its better to match the number than replace the other characters:

var matches = /(\-?\d*\.(?:\d+)?)/.exec(str);
if (typeof matches != 'undefined' && matches.length > 0) {
    var num = parseFloat(matches[1]);
}

Answer 4

You can try to use regexp:

/-?(\\d+\\.\\d+)[^\\w\\.]/g

DEMO

Answer 5

Try the following,

str.replace(/-?[0-9]+(\.[0-9]+)?/g,'')

                 OR 

str.match(/^-?[0-9]+(?:\.[0-9]+)?$/,'')