LSL Wiki : llListReplaceList

list llListReplaceList(list dest, list src, integer start, integer end)

Returns a list replacing the slice of the list dest from start to end with the list src. start and end are inclusive, so 0, 1 would replace the first two entries and 0, 0 would replace only the first list entry.

Using negative numbers for start and/or end causes the index to count backwards from the length of the list, so 0, -1 would replace the entire list.

If start is larger than end, the list returned is the list between start and end followed by src, so 6, 4 would return the 5th entry with src after that.

Example of Slices:

// (Note that this is not real code.)
list    foo = ["a", "b", "c", "d", "e", "f", "g"];
list    bar = ["0", "1"];
list    zot;
zot = llListReplaceList(foo, bar, 2, 5); // returns ["a", "b", "0", "1", "g"]
zot = llListReplaceList(foo, bar, 4, -1); // returns ["a", "b", "c", "d", "0", "1"]
zot = llListReplaceList(foo, bar, 4, 1); // returns ["c", "d", "0", "1"]

Note:
llListReplaceList does not manipulate dest directly. The list returned by this function is the modified version of the dest. See the following example:

Functional Example:

default {
    touch_start(integer total_number) {
        list foo = ["a", "b", "c", "d", "e", "f", "g"];
        list bar = ["0", "1"];
        foo = llListReplaceList(foo, bar, 2, 5); // to really return ["a", "b", "0", "1", "g"]
        // or done with the list hack
        foo = (foo=[]) + llListReplaceList(foo, bar, 2, 5); // to really return ["a", "b", "0", "1", "g"]
        llOwnerSay(llList2CSV(foo));
    }
}

To replace a stride in the list:

list UpdateSubListStrided(list src, list stride, integer start, integer stride_len) {
    return llListReplaceList(src, stride, start, start + stride_len - 1);
}

Question: Does the slice definied by start and end need to be the same length as src?
Answer: No, you can replace a slice with a longer or smaller src.

Question: I don't get it. It's not replacing my list.
Answer: No, llListReplaceList doesn't actually manipulate dest directly, rather it returns a new list containing the results. To manipulate a list directly, you need to do something like the functional example above. Alternatively, you can pass the result to a new list, and keep the original the same.

Compare with llList2List, llList2ListStrided, llListInsertList, llDeleteSubList, llList2Float, llList2Integer, llList2Key, llList2Rot, llList2String and llList2Vector.

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Functions | Lists

the examples above don't really work because of the subtil note: "This function does not manipulate dest directly. The list returned by this function is the modified version of the dest."

default
{
    state_entry()
    {
        llSay(0, "Hello, Avatar!");
    }

    touch_start(integer total_number)
    {
        list foo = ["a", "b", "c", "d", "e", "f", "g"];
        list bar = ["0", "1"];
        foo = llListReplaceList(foo, bar, 2, 5); // to really return ["a", "b", "0", "1", "g"]
        llOwnerSay(llList2CSV(foo));
    }
}

-- NonnuxWhite (2005-07-03 04:41:27)