A Collection of Code Snippets in as Many Programming Languages as Possible

This project is maintained by TheRenegadeCoder

Welcome to the Merge Sort in Mathematica page! Here, you’ll find the source code for this program as well as a description of how the program works.

```
(* Code *)
(* The function takes a Mathematica list of unsorted nonnegative integers: *)
mergeSort = list \[Function]
(* merge two sorted components *)
Apply[Function[{l, r},
First[ (* just the merged list *)
NestWhile[
(* merge one element from either the left or right list into output *)
Apply[Function[{m, l, r},
If[ (* use the first element of the left list if *)
(* the right list is empty, or the left list has elements and compares before the right *)
Length[r] == 0 \[Or] (Length[l] > 0 \[And] First[l] < First[r]),
{Append[m, First[l]], Rest[l], r},
{Append[m, First[r]], l, Rest[r]}]]],
(* begin with just the two components *)
{{} (* will be the merged list *), l, r},
(* while there are still elements in either the left or right list *)
Apply[Function[{m, l, r}, Length[l] > 0 \[Or] Length[r] > 0]]]]],
(* for each partition component, sort recursively until it contains no more than one element *)
If[Length[#] <= 1, #, mergeSort[#]] & /@ (
(* partition the list approximately halfway *)
#[list, Floor[Length[list]/2]] & /@ {Take, Drop})];
(* The outer function provides the 'user interface': *)
mergeSortMain = l \[Function]
Module[{e = "Usage: please provide a list of at least two integers to sort in the format \"1, 2, 3, 4, 5\""},
Catch[
StringRiffle[
mergeSort @
(* list must have more than one element *)
If[Length[#] > 1, #, Throw[e]] & @
Map[
(* convert string to integer, or throw *)
s \[Function] If[StringMatchQ[s, DigitCharacter ..],
FromDigits[s],
Throw[e]],
(* construct arguments to merge sort: list of items *)
StringSplit[l, ", "],
{-1} (* at each leaf *)],
", "]]];
(* Valid Tests *)
Print /@ mergeSortMain /@ {
"4, 5, 3, 1, 2",
"4, 5, 3, 1, 4, 2",
"1, 2, 3, 4, 5",
"9, 8, 7, 6, 5, 4, 3, 2, 1"
};
(* Invalid Tests *)
mergeSortMain[""]
mergeSortMain["1"]
mergeSortMain["4 5 3"]
```

Merge Sort in Mathematica was written by:

- Ben Hekster

If you see anything you’d like to change or update, please consider contributing.

No ‘How to Implement the Solution’ section available. Please consider contributing.

No ‘How to Run the Solution’ section available. Please consider contributing.