Difference between revisions of "String exploding"

(Undo revision 3102 by Robin (Talk))
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</source>
 
</source>
  
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This function acts similarly to the one above.  It differs in that it omits leading or trailing delimiters from the table it returns.  This means if the original string had leading or trailing delimiters, you won't be able to use table.concat to reverse it back into the original string.
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<source lang="lua">
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function string.explode2(s, d)
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  local t = {}
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    repeat
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      local pos1, pos2 = string.find(s, d)
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      t[#t + 1] = string.sub(s, 1, pos1 - 1)
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      s = string.sub(s, pos2 + 1)
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    until pos1 == nil
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    if #s ~= 0 then t[#t+1] = s end
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  return t
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end
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</source>
 
[[Category:Snippets]]
 
[[Category:Snippets]]

Revision as of 02:54, 6 April 2015

This function adds the ability to explode strings in Lua.

function string.explode(str, div)
    assert(type(str) == "string" and type(div) == "string", "invalid arguments")
    local o = {}
    while true do
        local pos1,pos2 = str:find(div)
        if not pos1 then
            o[#o+1] = str
            break
        end
        o[#o+1],str = str:sub(1,pos1-1),str:sub(pos2+1)
    end
    return o
end

Have an example:

tbl = string.explode("foo bar", " ")
print(tbl[1]) --> foo
-- since we added explode to the string table, we can also do this:
str = "foo bar"
tbl2 = str:explode(" ")
print(tbl2[2]) --> bar
-- to restore the original string, we can use Lua's table.concat:
original = table.concat(tbl, " ")
print(original) --> foo bar

This function acts similarly to the one above. It differs in that it omits leading or trailing delimiters from the table it returns. This means if the original string had leading or trailing delimiters, you won't be able to use table.concat to reverse it back into the original string.

function string.explode2(s, d)
  local t = {}
    repeat 
      local pos1, pos2 = string.find(s, d)
      t[#t + 1] = string.sub(s, 1, pos1 - 1)
      s = string.sub(s, pos2 + 1)
    until pos1 == nil
    if #s ~= 0 then t[#t+1] = s end
  return t
end