CODEWITHSUNDEEP
lua
sceiler
sceiler

Reputation: 1205

Substring on lua table for last 4 characters

I am trying to get the last 4 characters of a field in a lua table.

My csv file looks like this: 1234, http://myurl.com

local list = {}
for line in io.lines("x.csv") do
    local mediaId, fURL = line:match("([^,]+),([^,]+)")
    list[#list + 1] = { mediaId = mediaId, fURL = fURL }
end

print(list[1].mediaId) -- 1234
print(list[1].fURL) -- http://myurl.com
print(list[1].fURL.tostring().sub(list[1].fURL.tostring().len() - 4)) -- expected result: last 4 character of string, eg. .com

What I need now are the 4 last characters. It does not matter what they are, no need for any checks just the 4 last characters. My code above causes a "attempt to call field 'tostring' (a nil value)" error. What do I need to do to correct it?

Upvotes: 1

Views: 726

Answers (2)

sceiler
sceiler

Reputation: 1205

local bla = string.len(tostring(list[1].fURL)) - 3
print(string.sub(tostring(list[1].fURL), bla)) -- last 4 character, yes minus 3 = last 4 character.

Upvotes: 2

hjpotter92
hjpotter92

Reputation: 80639

You can store them as a new key in the table (The function used is string.sub):

for line in io.lines("x.csv") do
    local mediaId, fURL = line:match("([^,]+),([^,]+)")
    list[#list + 1] = { mediaId = mediaId, fURL = fURL, last = fURL:sub(-4) }
end

and reference them outside of the loop as:

print( list[1].last )

Upvotes: 3

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