Removing space from string with regex

Question

I can find spaces in the following string:

"____Input from ABC" << please note there are 4 spaces at the beginning of this string

using this regex:

[a-z] [a-z]

How can I replace"t f" with "tf" and "m A" with "mA"? I guess I have to use groups but I don't remember how. Any advice would be appreciated.

P.S. Please note that there are 4 spaces at the beginning of the string I don't want to remove them.

Answer 1

Just use \s and replace with empty string "". You could also use literal space which too will work perfectly. Just remember to use global flag.

That is, use /\s/g or / /g and replace with ""

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Regarding your update, you could still use the above regex and then just add four spaces to the string, which is quite efficient. If you still want a regex, you could use

(?<=\w)\s(?=\w)

and replace with ""(Empty string)

Answer 2

Depending on the language you are using, you should have a "replace" function

You have to use capturing group, like so :

([a-z]) ([a-z])

http://www.regular-expressions.info/refcapture.html

and then use the function to get them back in the pattern you want :

newString = oldString.replace("([a-z]) ([a-z])", "\1\2")

\X reference the Xth group of parenthesis