Regular expression to remove link in String in Swift

Question

I have bunch of strings I receive from service and need to alter the text to extract and remove 3 types of link as mentioned below

anchor - [anchor:info]Account Details[/anchor]
action -  [action:contact]Contact info[/anchor]
link-to - [link-to:register]Create An Account[/link-to]

Example full length text from service:

1. "There's a problem with your [anchor:info]Account Details[/anchor]."
2. "There's a problem with your [anchor:rewards]Sign Up For Rewards[/anchor]."
3. "We didn't recognize this account. Please re-enter your email or [link-to:register]Create An Account[/link-to]."

And the expected result should be:

1. "There's a problem with your Account Details."
2. "There's a problem with your Sign Up For Rewards."
3. "We didn't recognize this account. Please re-enter your email or Create An Account."

I figured I will use replacingOccurrences function to achieve this. But I haven't cracked the regular expression for my required format.

let aString = "There's a problem with your [anchor:info]Account Details[/anchor]."
let newString = aString.replacingOccurrences(of: "regex here", with: " ", options: .regularExpression, range: nil)

I can either have 3 separate regex to match the 3 cases or have one regex which can handle below:

[any_link_type:any_identifier]Any Text[/any_link_type]

Can some regex gurus help me with this?

Answer 1

Try this pattern ^([^[]+)\[([^:\]]+)[^\]]*\]([^[]+)\[\/\2\]

And replace it with \1\3.

Explanation:

^ - beginning of the string

([^[]+) - match one or more characters other than [ and store in capturing group

\[ - match [ literally

([^:\]]+) - match one or more characters other than : or ] and store in capturing group

[^\]]* - match zero or more characters other than ]

\] - match ] literally

([^[]+) - match one or more characters other than [ and store in capturing group

\[\/ - match [/ literally

\2 - match the same text as was matched in second capturing group (so it matches closing tag, like anchor)

\] - match ] literally

Demo