Finding the prefix of a string

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#1

Hello!

I have a few progress systems which are duplicated for every player, the issue is that it can cause a bit of lag, so I am trying to destroy it for the local player. I can do that, the issue is that I don’t know how to find the prefix of the string.

So, each time it’s duplicated for each player, on the server’s side, its name is “progress(user’s id)”. How would I find if the name starts with “progress”?

I tried doing some research, and found string:find(), however that seems to not be in the Roblox Lua library. Where do I go from here?

#2

Roblox has string:find(), it totally exists.

For any object in the library string.function(str), you can just do str:function().

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#3

When you say string:find(), do I do the string’s variable, or the actual word “string”?

#4

The string’s variable. So:

local str = "hello"

print(str:find("ell")) --2, 4
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#5

What is the 2,4 at the end? Or is that optional?

#6

No, that is what it prints. Basically, it returns the start of the match and the end. So, ell starts 2 characters in and ends 4 characters in. If it doesn’t find it, it returns nil. So, to catch that, you can do:

local start, End = str:find("ell")
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#7 
 local str = "progress123"
 if str:find("progress") then -- found, or else it would be nil
    local id, _ = str:gsub("progress", "") -- get the id as well
    print(id)
 end

Another approach would be to see whether the id is contained in there instead of finding out whether ‘progress’ is.

 if str:match("%d") then
   print(str:match("%d+"))  -- gets the id, %w+ for all of it
end
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