How to Sort one collection based on another one and other condition

Question

I have a list which I want to sort:

List<string> temp = {
    "Mina 1", "Mina 2", 
    "Planning 3", "Planning 2", "Planning 1", "Planning 4", 
    "Kira 2", "Kira 1"};

List to sort:

// Sort items based on the following order of name
List<string> listToSort= {"Planning", "Mina", "Kira" };

I'm trying to sort temp based on listToSort and number increase

expected Result:

List<string> temp = {
    "Planning 1", "Planning 2", "Planning 3", "Planning 4",
    "Mina 1", "Mina 2",  
    "Kira 1", "Kira 2"};

Which problems do you face when trying? It's not clear where you need help. — Gert Arnold, Aug 15 '21 at 08:51

score 1 · Accepted Answer · answered Aug 15 '21 at 06:49

1

Since these are lists you can use a combination of FindIndex and StartsWith:

var result = temp
    .OrderBy(t => listToSort.FindIndex(s => s.StartsWith(t)))
    .ThenBy(t => t);

answered Aug 15 '21 at 06:49

Zohar Peled

score 1 · Answer 2 · answered Aug 15 '21 at 06:58

While not the most efficient, one option is to use SelectMany:

var sorted = listToSort.SelectMany(sortKey => temp.Where(t => t.StartsWith(sortKey)).OrderBy(s => s));

For every string in listToSort, SelectMany finds all related string in temp and orders by them.

If you need natural sorting (so "Kira 11" will be sorted after "Kira 9"), you can add a comparer, for example Natural Sort Order in C#

2 Answers2