Question

I am trying to validate text that follows the pattern below:

• Must have the text “point(” at the beginning
• Must follow it by a Latitude numerical value with up to 5 decimal places (example: 42.12345)
• Must follow it by a comma “,”
• Must follow it by a Longitude numerical value with up to 5 decimal places (example: -81.12345)
• Must follow it by a closing parentheses “)”

Matching example:

• point(42.12345,-81.12345)

Any help is greatly appreciated.

Thanks.

Answer 1

You can easily build your regex with a little bit of break-up here.

• To match point( at the beginning, use – ^point\(
• To match a latitude or longitude numbers, use – [-]?\d+(?:\.\d+)?
• And again, to match ) at the end, use \)$.

For [-]?\d+(?:\.\d+)?, here’s an explanation: –

• [-]? – matches an optional negative (-) sign at the starting (? quantifier at the end means 0 or 1)
• \d+ – matches one or more digits
• (?:\.\d+)? – matches an optional decimal, followed by one or more
digits. dot(.) is a special meta-character in Regex, so you need to escape it, if you want to match it.

Also, to limit your number of digits to 5, you can use – \d{1,5} instead of \d+, which matches minimum 1 and maximum 5 digits.

^(caret) and $(dollar) anchors matches the beginning and end of the string.

So, here’s your regex: –

^point\([-]?\d+(?:\.\d{1,5})?,[-]?\d+(?:\.\d{1,5})?\)$