Help with string.gsub()!

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#1

Helloo!! I’ve been scripting for a long time now but there’s something I’ll never understand. string patterns :broken_heart:

I’m trying to replace a part of a string using string.gsub() if they have these properties:

  • They are the start of the string — no spaces or any characters before.
  • Starts with <prefix and ends with > (just the part, not the whole strings end)
  • The prefix part can be followed by spaces or other strings separated by spaces
    • In this case, the strings should be separated by a space from prefix (Ex.: “<prefixlol>” shouldnt count)

Overall, the accepted strings should look like these;

  • “<prefix>” & “<prefix> bla bla bla”
  • “<prefix >” (space between prefix and ‘>’)
  • “<prefix but not>”
  • “<prefix again >”

Thanks in advance!! :​D

:grey_exclamation: It seems like the < and > char hides text on the forum, so I recommend putting a \ before them lols
#2

I don’t think you can do that with just a gsub() you’d have to first check if the string has what you want using other string commands such as match and sub and only then doing gsub

#3

Can you provide examples and your desired results for those examples? The current examples seem to be cut off or unclear.

But, if you want to match <someStringHere> only at the start, something like this could work:

local example = "<someStringHere>"
local replacedString = string.gsub(example, "^%b<>", "hello")
print(replacedString) --> "hello"
  • ^ matches the start of the string.
  • %b is the flag for symmetric matching, so %b<> matches the first <, then keeps on searching until it finds an equivalent quantity of >.

By the way, if you don’t want the formatting to hide things, you can use backticks <like this> and it will display properly:

image

1 Like
#4

Of course!
Basically <mark ...> and <mark> should be replaced. (mark ... represents the cases where mark is followed a space and then any string)

"<mark> lol"  -> "hello lol"
--mark.

"<mark > againnn"  ->  "hello againnn"
--mark with a space before ">"

"<mark but more words> world"  ->  "hello world"
--mark followed by some words

"<mark example > :P" -> "hello :P"
--mark followed by words and space before the ">"

"<mark but_its_weird> :P" -> "hello :P"
--mark followed by word(s) but in another format

"<markbutevil> example" -> "<markbutevil> example"
"<marklol thing> example" -> "<marklol thing> example"
--mark followed by word(s) WITHOUT a space first
--this case shouldnt be replaced/qualified

If you need more examples then tell me

#5

So if I’m understanding correctly, you want to match strings that start with <mark and end with >, but if any extra words are in between, there has to be a space.

This should work:

local example = "<mark but_its_weird> :P"
local replacement = "hello"
local result = string.gsub(example, "^%b<>", function(capture)
	print(capture) --> "<mark but_its_weird>"
	
	local sixthChar = string.sub(capture, 6, 6)
	if sixthChar == " " or sixthChar == ">" then
		return replacement
	else
		return capture
	end
end)
print(result) --> "hello :P"

We are checking if the 6th character is a space or the ending “>” to see if it’s valid or not. If it is, sub in the replacement. If it isn’t, return the original capture.

1 Like
#6 
local function replace_prefixes(text, prefix, replacement)
  local pattern = "^\\<" .. prefix .. "%s+>" -- or "^\\<" .. prefix .. "[^\\>]+\\>" Im dont sure
  local new_text = string.gsub(text, pattern, replacement)
  return new_text
end
#7

Thanks!! I modified the code a bit and got it working :​)

--function for string.gsub
local mark = 'mark'
local check = string.sub(str,1,#mark+2)
if check == '<'..mark..'>' or check == '<'..mark..' ' then
	return 'replacement'
else
	return str
end