Conditional Matching with Javascript Regular Expressions

Question

Conditional Matching with Javascript Regular Expressions

My strings are formatted like this:

#WTK-56491650H #=> want to capture '56491650H'
#M123456       #=> want to capture 'M123456'

I am trying to extract everything after the # character, unless there is a dash. In that case, I only want to capture what comes after the dash. I have been experimenting with JavaScript regex conditionals, but I can't seem to get it right. The current expression only matches what's after the # and nothing else.

Here is my current regex pattern:

/((?=-{1})-(.+)|(?!-{0)#(.+))/

You can view a demo here.

javascript regex

Answer 1

Answer №1

Utilize the following regular expression pattern that includes an optional match to capture all content between # and -:

/#(?:[^-]*-)?([^#-]+)$/mg

Enhanced RegEx Example

Answer 2

Utilize the following regular expression pattern that includes an optional match to capture all content between # and -:

/#(?:[^-]*-)?([^#-]+)$/mg

Enhanced RegEx Example

Answer 3

Answer №2

Consider this alternative solution that utilizes non-capturing groups such as (?:stuff). This approach eliminates the need to search through result groups to locate the desired string.

(?:#)(?:[\w\d]+-)?([\w\d]+)

This method first removes the # character, followed by discarding any content leading up to and including the - character (if present), and then captures the remaining text as your desired match.

Answer 4

Consider this alternative solution that utilizes non-capturing groups such as (?:stuff). This approach eliminates the need to search through result groups to locate the desired string.

(?:#)(?:[\w\d]+-)?([\w\d]+)

This method first removes the # character, followed by discarding any content leading up to and including the - character (if present), and then captures the remaining text as your desired match.

Answer 5

Answer №3

When crafting a single regular expression, the key is to ensure that your full match includes the hash and/or dash that you are using to specify a valid string. However, by grouping parts of the match, you can extract the specific information you need.

To start, indicate that the string must begin with a hash by including # in your regex.

Next, exclude anything preceding and up to a dash with (.*-)?, making this part optional by adding a question mark (in case there is no dash).

Lastly, capture the remaining characters into a final group, which will serve as your desired answer with (.*).

The complete expression would then be #(.*-)?(.*), as suggested by Lux.

Answer 6

When crafting a single regular expression, the key is to ensure that your full match includes the hash and/or dash that you are using to specify a valid string. However, by grouping parts of the match, you can extract the specific information you need.

To start, indicate that the string must begin with a hash by including # in your regex.

Next, exclude anything preceding and up to a dash with (.*-)?, making this part optional by adding a question mark (in case there is no dash).

Lastly, capture the remaining characters into a final group, which will serve as your desired answer with (.*).

The complete expression would then be #(.*-)?(.*), as suggested by Lux.

Conditional Matching with Javascript Regular Expressions

Answer №1

Answer №2

Answer №3

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