Decorating numbers inside the string with the thousand separator

Question

A have a string that contains one ore more number. The numbers are normally integers, but also decimal could be expected at some point. I looking for a solution that adds the thousand separator(. or ,) to all numbers inside the string.

For example

100000 -> ?100,000?
?100000?50000 -> ?100,000?50,000
X10000.5? -> X100,00.5?

Any idea?

Take a look at this: http://msdn.microsoft.com/en-us/library/dwhawy9k.aspx — Jan Köhler, Dec 29 '14 at 13:27
? represents just a normal character that has to be preserved in the result. For example for "TestX10000FOO" i expect to get "TestX10,000FOO". — Sebastjan, Dec 29 '14 at 13:28
So you have some strings with randomly nested numbers in them? — Jan Köhler, Dec 29 '14 at 13:30
Yes. That is right. A string can contain multiple numerical values in random places. Basically, I have to find all numbers inside the string and decorate them with thousand separator. — Sebastjan, Dec 29 '14 at 13:33
Thean take one of [these answers](http://stackoverflow.com/questions/4734116/find-and-extract-numbers-from-a-string) and combine the output with `.ToString("N")` — Jan Köhler, Dec 29 '14 at 13:37
khlr Unfortunately "ToString(XX" works only, with a "well formated" single number. In order to use .ToString( withe the format parameter you need a number. — Sebastjan, Dec 29 '14 at 14:00

score 1 · Answer 1 · answered Dec 29 '14 at 14:17

A hacky solution in pure regex is to replace all occurences of

(?<=\d)(\d{3})(?!\d)

with ,$1. This is, of course, very limited, as it only adds one separator per number, and also adds separators after a comma. See regex101 demo.

A far cleaner solution is to search for numbers using a regex such as \d+(?:\.\d+)?, convert each match to a number, and re-insert the formatted number into the text.

(You'll have to forgive me for not including any code, but I haven't coded in C# in ages.)

Decorating numbers inside the string with the thousand separator

1 Answers1