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This once again shows that optimizations should always be based on measurements and not intuition. Intuition lies. :)

-----Original Message-----
    From: "William Trenker"<>
    Sent: 23.8.05 21:55:56
    To: "Lua list"<>
    Subject: Re: Lua Basics: tables as lists?
      On 8/22/05, Rici Lake <> wrote:
    > For loops are not expensive
    > > myList = {"a", "b", "cde"}
    > > myListString = "|" .. table.concat(myList, "|") .. "|"
    > > a = "cde"
    > > if string.find(myListString, "|"..a.."|") then
    > >     print("found!")
    > > else
    > >     print("not found")
    > > end
    > That is very expensive
    You're right.  I ran some timed tests over large lists and the for
    loop was an order of magnitude faster than concatenating the table
    values into a string and doing a string.find.
    My intuition was wrong.  I assumed that a for loop was expensive
    because it meant running the code in that loop through the interpreter
    over and over.  I thought that the single string.find, being done in
    C, would be faster.  But, in fact, the time to run the preparatory
    table.concat -- for large lists -- is comparitivly very slow  and does
    indeed make that approach very expensive.
    I'm really beginning to respect the efficiency of the Lua interpreter.
    Thanks for the insight,