Checking negative and positive decimal numbers with RegEx

Question

I am trying to create a regular expression that will allow both negative and positive decimal numbers with the following rules.

• after the decimal point there can be no more than two digits
• Decimal point optional
• Total length, including decimal point, must not exceed 12 char
• if there is no decimal point, the maximum length must not exceed 9 char

Can anyone help me out? Thanks a lot in advance.

Answer 1

Check out this regex.

^[+-]?[0-9]{1,9}(?:\.[0-9]{1,2})?$ 

In this regex

• Sign
• is optional
• at least one and a maximum of 9 digits as an integer part
• if there is a decimal point, at least one and two two digits after it.

Answer 2

This is pretty simple, since 12 - 9 == 3 for two decimal places + a dot.

 var re = new RegExp('^-?\\d{1,9}(\\.\\d{1,2})?$'); 

authorizes

• -123456789
• -123456789.1
• -123456789.12
• 0
• 0.12

but will not accept

• 01234567890123 more than 12 divisions
• 123. period without decimal places
• 123.123 more than two decimal places
• . or .12 (missing 0)

Answer 3

My own regex:

 var rgx = /^(-{1}?(?:([0-9]{0,10}))|([0-9]{1})?(?:([0-9]{0,9})))?(?:\.([0-9]{0,3}))?$/; 

Answer 4

 var NumberToValidate = 48428; var valid = /^([0-9]*[1-9][0-9]*)$/.test(NumberToValidate); { if (!valid) alert("Invalid Quantity!!\nThe Quantity cannot be Zero\n or a part of a Unit !"); return false; } 

Answer 5

 /(?:^(?:(?:[1-9][0-9]{1,})|0)\.[0-9]{1,}$)|^[1-9]+[0-9]*$/