What do you do to fix this string manipulation "match" returning nil?
Here's my script:
01 | Players.PlayerAdded:Connect(function(plr) |
02 | plr.Chatted:Connect(function(msg) |
03 | -- Check for admin here. |
04 | if(msg:sub(1,1)=="/")then |
05 | local command, arg1, arg2 = msg:match("^%/(%S+)%s+(%a+)%s(.+)$") |
06 |
07 | print(command) |
08 | print(arg1) |
09 | print(arg2) |
10 | end |
11 | end) |
12 | end) |
Everything's fine, I define the service Players elsewhere but if I added it this would be a standalone script.
The area of problem is here:
1 | local command, arg1, arg2 = msg:match("^(%S+)%s+(%a+)%s(.+)$") |
And it works like I want it to. Examples:
1 | "/displayMessage all Hey guys!" |
2 |
3 | print(command) -- displayMessage |
4 | print(arg1) -- all |
5 | print(arg2) -- Hey guys! |
However some commands will only require two arguments, but then everything's nil.
1 | "/kill me" |
2 |
3 | print(command) -- nil |
4 | print(arg1) -- nil |
5 | print(arg2) -- nil |
How could I fix this?
This code is mostly from one of my past questions.
I modified Blue's solution a little to fit my new situation here, but I'm still really bad with string manipulation. :c
Thanks for any help!
1 answer
With string.match nil will be returned if there is no capture found / matched.
For an admin script it might be best to build a argument table as this will support a ever changing amount or args ie one function to manage them all.
I find that it can simplify an admin script to just check for the admin command prefix in your case the / then cut out the prefix.
1 | -- we should also check the string size before |
2 | if msg:sub(1,1) == '/' then |
3 | msg = msg:sub(2) -- remove the prefix |
4 | end |
Now that we no longer have the prefix we can split the string using the white space followed by a varying number of characters ie [o or more white space characters] [as many non white space characters as possible]
We can represent this as a string pattern like so %S-(%a+).
But this will not capture any players with any numbers or commands with punctuation in so we need a set resulting in our finished pattern %S-([%a%d%p]+)
Example:-
01 | local testData = { |
02 | '/kill me ??', |
03 | '/ kill me ??', |
04 | '/kill me', |
05 | '/ kill me', |
06 | '/kill', |
07 | '/ kill ', |
08 | 'adsa', |
09 | '/displayMessage all Hey guys!', |
10 | 'a', |
11 | '/kill guest11', |
12 | '/kill me!!' |
13 | } |
14 |
15 | for i=1, #testData do |
Output:-
01 | --[[ |
02 | --------- Test 1 ----------- |
03 | kill 4 |
04 | me 2 |
05 | ?? 2 |
06 | --------- Test 2 ----------- |
07 | kill 4 |
08 | me 2 |
09 | ?? 2 |
10 | --------- Test 3 ----------- |
11 | kill 4 |
12 | me 2 |
13 | --------- Test 4 ----------- |
14 | kill 4 |
15 | me 2 |
I hope this helps
