Swift finding and changing range in attributed string

Question

What would be the best way to change this string:

"gain quickness for 5 seconds. <c=@reminder>(Cooldown: 90s)</c> only after"

into an Attributed String while getting rid of the part in the <> and I want to change the font of (Cooldown: 90s). I know how to change and make NSMutableAttributedStrings but I am stuck on how to locate and change just the (Cooldown: 90s) in this case. The text in between the <c=@reminder> & </c> will change so I need to use those to find what I need.

These seem to be indicators meant to be used for this purpose I just don't know ho.

You need to use NSRegularExpression. You can search a lot of examples in SO or google. — Ryan
– Ryan, Commented Aug 8, 2018 at 21:14

Cristik · Accepted Answer · 2018-08-28 07:13:13Z

1

First things first, you'll need a regular expression to find and replace all tagged strings.

Looking at the string, one possible regex could be <c=@([a-zA-Z-9]+)>([^<]*)</c>. Note that will will work only if the string between the tags doesn't contain the < character.

Now that we have the regex, we only need to apply it on the input string:

let str = "gain quickness for 5 seconds. <c=@reminder>(Cooldown: 90s)</c> only after"
let attrStr = NSMutableAttributedString(string: str)
let regex = try! NSRegularExpression(pattern: "<c=@([a-zA-Z-9]+)>([^<]*)</c>", options: [])
while let match = regex.matches(in: attrStr.string, options: [], range: NSRange(location: 0, length: attrStr.string.utf16.count)).first {
    let indicator = str[Range(match.range(at: 1), in: str)!]
    let substr = str[Range(match.range(at: 2), in: str)!]
    let replacement = NSMutableAttributedString(string: String(substr))
    // now based on the indicator variable you might want to apply some transformations in the `substr` attributed string
    attrStr.replaceCharacters(in: match.range, with: replacement)
}

edited Aug 28, 2018 at 7:13

answered Aug 8, 2018 at 22:10

Cristik

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3 Comments

Joshua Guenard Over a year ago

hey this answer worked great thank you so much. I am having a problem though with when there are more than one matches because on the second time through the for loop the range of the string was changed and when it tries to replace the second match it says it's out of range. Any ideas to help with that?

Cristik Over a year ago

@JoshuaGuenard I fixed the issue, replaced the for loop on the original string to a while loop of the attributed string being worked on.

Joshua Guenard Over a year ago

is there a good reference for how to construct regex? Now there is another instance with a different pattern I'd like to extract.

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