A thread was recently made about string.sub working incorrectly, but the question was deleted before I could answer. The problem was an easy one to make; the code looked similar to:
local s = "Hello world!"
print(s:sub(1, 5) == "ell") --> false -- why?
I'll post my answer to this question below for those who may come across a similar issue.
Your issue is in inclusiveness. The full syntax of string.sub is:
s:sub(int i, int j)/string.sub(string s, int i, [int] j)
Return the substring of s that starts at i and ends at j; i and j can be negative. If j is absent, then it is assumed to be equal to -1 (which is the same as the string length).
i and j are inclusive; they are included in the substring:
local s = "Hello world!"
print(s:sub(2, 4)) --> ell -- e is the 2nd character, l is the 4th character.
In your script, you do not account for this inclusion, which is why you are receiving unexpected results.
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someone asked a question like this which i answered to see that the post was deleted. i didn't want to waste my answer ¯_(?)_/¯
You are assuming that the index of the substring begins at 0, which in fact in Lua, begins at 1!
local s = "Hello world!"
print(s:sub(1, 5));
would print Hello. Not ello which is what you are assuming right now. Many other languages's index begins at 0 which is why you are confusing yourself right now.
To fix your problem, simply start from 2.
local s = "Hello world!"
print(s:sub(2, 5) == "ello");
which would evaluate to true.
That is the real issue here. There really is nothing wrong with the syntax itself. It is simply a Logical Error.
He was making a self answer...
He isn't supposed to be and he was not addressing the real issue. So I decided to answer it.
This discussion is preserved as it was. New answers, comments, and votes are closed.
4 comments
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There's nothing wrong with self answering a question because in the case that someone asked a question, received or didn't receive an answer, and deleted the question, doing this will help people in the future.
Also, anyone able to moderate, please vote to lock this so there won't be anymore spamming of question marks
Questions like these should be moved to Forums. Not here