Check if table value starts with - lua

Question

local maps = find.File("maps/*.bsp", "GAME")
map = (maps[math.random( #maps )])
print("Map randomized to " .. map )
This code above works on "ULX" on Garry's Mod, it uses find.File to read the directory of garrysmod/maps and return (in TABLE) all of the files in it ending with .bsp (all of the maps), however I do not wan't it to include maps that begin with certain parts, like "arena_" and "gm_", is there a way I can go about removing them and/or making it keep checking until It gets a map not beginning with that.
Any way I could do this? and preferable pure Lua please.
Oh and the site I'm using to test it is MOAIFiddle

Answer 1

It looks like the function you meant is file.Find instead of find.File.
http://wiki.garrysmod.com/page/file/Find
The following should work in Garry's Mod.
local maps = {}
local ignoredPrefixes = {"gm_","arena_"}
for _,map in ipairs(find.File("maps/*.bsp", "GAME"))do
local hasPrefix=false
for _,prefix in ipairs(ignoredPrefixes)do
if string.Left(map,string.len(prefix)) == prefix then
hasPrefix=true
break
end
end
if not hasPrefix then
table.insert(maps,map)
end
end
local randomMap = table.Random(maps);
print("Map randomized to "..randomMap)
What it does is read all maps in maps/ and then add all maps that do not have a certain prefix, defined in ignoredPrefixes, to the maps table.
When it is done doing so, a random map will be selected from the table.