Regex for number at the end of string?

Question

I want to find out if a string ends with number (with/without decimal). If it ends, I want to extracts it.

"Test1" => 1
"Test"  => NOT FOUND
"Test123" => 123
"Test1.1" => 1.1

I have missed a few details.
1. Prior to number, string can contain special characters also
2. It is single line, not multiline.

Solution 1

give this pattern a try,

\d+(\.\d+)?$

A version with a non-capturing group:

\d+(?:\.\d+)?$

Solution 2

Matches line start, any chars after that and a a number (with optional decimal part) at the end of the string (allowing trailing whitespace characters). The fist part is a lazy match, i.e. it will match the lowest number of chars possible leaving the whole number to the last part of the expression.

^.*?(\d+(?:[.,]\d+)?)\s*$

My test cases

"Test1
"Test
"Test123
"Test1.1
test 1.2 times 1 is 1.2
test 1.2 times 1 is ?
test 1.2 times 1 is 134.2234
1.2

Solution 3

Use the following regex in c# (\d+)$

Solution 4

A regex for a string that ends with a number: @"\d$". Use http://regexpal.com/ to try out regexes.

Of course, that just tells you that the last character is a number. It doesn't capture anything other than the last character. To capture the number only this is needed: @"\d*\.?\d+$".

If your string can be more complicated, eg "Test1.2 Test2", and you want both numbers: @"\d*\.?\d+\b".

Solution 5

use this regex [a-zA-Z]+\d+([,.]\d+)?\b$ if you want digit only use this one (?<=[a-zA-Z]+)\d+([,.]\d+)?\b$

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Comments

[Johanna Larsson]

@JoannaTurban the regex works for the last example too. It just checks whether the last character in the string is a number.

[Johanna Larsson]

@Esailija ah I misunderstood, I thought he wanted to know if the string ended with a number. In that case he could just grab the whole string, was my reasoning!

[Joanna Derks]

if you make the dot and the digits after the dot separate optional groups you can end up with a match "1."

[Johanna Larsson]

@JoannaTurban fair point, I wonder if .2 should be a valid number