Is there an easy way to split a string like this:
M34a79 or M2ab943 or M4c4
into
M,34,a,79 or M,2,ab,943 or M,4,c,4
without any separators?
-
2Leave the question as originally asked and add the solution as an answer.lhf– lhf2013-10-25 15:58:40 +00:00Commented Oct 25, 2013 at 15:58
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3 Answers
You can do it with a pair of gsub calls:
x = "M34a79 or M2ab943 or M4c4"
x, _ = x:gsub( "(%d)(%a)", "%1,%2" )
x, _ = x:gsub( "(%a)(%d)", "%1,%2" )
print( x )
M,34,a,79 or M,2,ab,943 or M,4,c,4
Might not work in all cases, but does work on your example.
3 Comments
Lukas
Yes, it works! :) Is it possible to store each of these values in variables?
Kogitsune
Would you want it to be a table of them, like { "M", "34", "a", "79" }, { "M", "2", "ab", "943" }, { "M", "4", "c", "4" } ?
Yu Hao
You don't need the
_, just x = x:gsub( "(%d)(%a)", "%1,%2" ) is enough.If you don’t mind using the LPEG library:
local lpeg = require "lpeg"
local C, Ct, P, R = lpeg.C, lpeg.Ct, lpeg.P, lpeg.R
local lpegmatch = lpeg.match
local extract
do
local digit = R"09"
local lower = R"az"
local comma = P","
local space = P" "
local schema = Ct( C(P"M")
* (digit^1 / tonumber)
* C(lower^1)
* (digit^1 / tonumber))
local extractor = Ct((schema + 1)^0)
extract = function (str)
return lpegmatch (extractor, str)
end
end
This will match all sequences of characters of the input that consist of (in that order)
- the letter
M, - a sequence of 1 or more decimal digits,
- a sequence of 1 or more lowercase characters, and
- another sequence of 1 or more decimal digits.
When processing the input each match is put in a subtable,
the digits are converted to Lua numbers on the fly.
Since the question requested it, the leading M is included
in the entries.
Usage example:
local data = extract [[M34a79 or M2ab943 or M4c4]]
for i = 1, #data do
local elm = data[i]
print (string.format ("[%d] = { [1] = %q, [2] = %d, [3] = %q, [4] = %d },",
i, table.unpack (elm)))
end
Output:
[1] = { [1] = "M", [2] = 34, [3] = "a", [4] = 79 },
[2] = { [1] = "M", [2] = 2, [3] = "ab", [4] = 943 },
[3] = { [1] = "M", [2] = 4, [3] = "c", [4] = 4 },
Comments
Solution:
http://www.coronalabs.com/blog/2013/04/16/lua-string-magic/
function string:split( inSplitPattern, outResults )
...
end
function val(x)
x = x:gsub( "(%d)(%a)", "%1,%2" )
x = x:gsub( "(%a)(%d)", "%1,%2" )
Table = string.split(x,",")
for i = 1, #Table do
print( Table[i] )
end
end
val("M3a5")
returns M 3 a 5