I need to match a pattern for validation . I want to match a decimal number where numeric part can have upto 14 digits including + or - without 0 and after decimal has upto 4 digits. Valid patterns are :
+1.23
9857.6543
-745290.0
Invalid patterns are:
0
0.00
1.23456
I have tried ^[0-9]{0,14}\.[0-9]{0,4}$.
I am not getting how to match for +,- and 0 condition
Short answer: ^[+-]?[1-9][0-9]{0,13}\.[0-9]{1,4}$
^ - start of string
[+-]? optionally, one between + and -
[1-9][0-9]{0,13} - a 14 digit number that doesn't start with 0
\. - decimal separator, has to be escaped or it will mean "any one character"
[0-9]{1,4} - up to 4 decimal digits
$ - end of string
This might work ^(\+|-)?(([1-9]|0(?=0*[1-9]))[0-9]{0,13}(\.[0-9]{1,4})?|0{1,14}\.(?=0*[1-9])[0-9]{1,4})$
^(\+|-)? - starts with +/-(([1-9]|0(?=0*[1-9]))[0-9]{0,13}(\.[0-9]{1,4})? - absolute value >= 1| - or0{1,14}\.(?=0*[1-9])[0-9]{1,4} - 0.**** with at least 1 non-zero digit)$ - endconst testcases = [
'+1.23',
'9857.6543',
'-745290.0',
'1.0',
'1.00',
'12',
'0.01',
'+001.01',
'0',
'0.00',
'1.23456',
'0.0',
'12.'];
const regex = /^(\+|-)?(([1-9]|0(?=0*[1-9]))[0-9]{0,13}(\.[0-9]{1,4})?|0{1,14}\.(?=0*[1-9])[0-9]{1,4})$/;
testcases.forEach(n => console.log(`${n}\t - ${regex.test(n)}`));The pattern:
^[+-]?[^\D0]\d{0,13}\.\d{1,4}(?!\d)
matches the first 3 but not the second 3. [^\D0] is, if I'm not mistaken, strictly the same as [123456789], but slightly more compact.
You can assert that the string does not start with 1 or more zeroes, followed by an optional dot and optional zeroes.
Then match 1-14 digits and optionally a dot and 1-4 digits, which would also allow for 00001 for example
^(?!0+\.?0*$)[+-]?\d{1,14}(?:\.\d{1,4})?$
The pattern matches:
^ Start of string(?!0+\.?0*$) Negative lookahead, assert not 1+ zeroes, optional dot and optional zeroes[+-]? Optionally match + or -\d{1,14} Match 1-14 digits(?:\.\d{1,4})? Optionally match . and 1-4 digits$ End of stringHow about this?
^(?!0\.?0*$)[\+\-]?[0-9]{1,14}\.?[0-9]{0,4}$
Note: this does not match decimals without a leading 0 like .123 and does not match numbers with spaces in between the + or -. Though, these could be added to the pattern.
Requiring a non-zero digit before a . eliminates fractions of whole numbers, like 0.123.
Also, if you don't want integers and only want decimals, you will need to modify to make the . required:
^(?!0\.?0*$)[\+\-]?[0-9]{1,14}\.[0-9]{0,4}$
12.or12valid?0.0,1.0,1.00