Sorting List of String by their rank

Question

Given a

List<string> s=new List<string>{"a","b","c"}
and 
List<double> srank=new List<double>{2,3,1}

I wish to sort s by the number of srank in descending order i.e. after sorting

s={"b","a","c"}

what's the easiest way for doing this？

Any reason you aren't storing these as objects instead of 2 lists? — Kevin DiTraglia, Sep 24 '13 at 11:53

Kamil Budziewski · Accepted Answer · 2013-09-24T12:05:06.323

9

Try this

   var sorted = s
      .Zip(srank, (x,y) => new { s = x, rank = y })
      .OrderByDescending(x => x.rank)
      .Select(x => x.s)
      .ToList();

Read more about OrderByDescending

EDIT:

There is a very short solution using arrays: if s and srank were Arrays we can do this:

Array.Sort(srank,s);

edited Sep 24 '13 at 12:05

answered Sep 24 '13 at 11:49

Kamil Budziewski

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s = x; rank = y; part give me error=>',' or '}' expected – william007 Sep 24 '13 at 11:55
@william007 sorry edited, there was a typo :) thanks for mentioning – Kamil Budziewski Sep 24 '13 at 11:57
@wudzik Still a `;` to much though :) – flindeberg Sep 24 '13 at 12:00
@flindeberg ah, thanks, writing without IDE is pain in the ... :) – Kamil Budziewski Sep 24 '13 at 12:01
1

Your example using Array.Sort() has the parameters the wrong way around. – Matthew Watson Sep 24 '13 at 12:03
@MatthewWatson thanks, good point edit – Kamil Budziewski Sep 24 '13 at 12:04

score 1 · Answer 2 · answered Sep 24 '13 at 12:03

1

If I were you I'd use a List<Tuple> a Dictionary or create a new class then do

var dictionary = new Dictionary<string, double>
{
    { "a", 2 },
    { "b", 3 },
    { "c", 1 }
};

var result = dictionary.OrderByDescending(d => d.Value).Select(d => d.Key);

answered Sep 24 '13 at 12:03

dav_i

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a bit overkill I think – Kamil Budziewski Sep 24 '13 at 12:06
Depends on the situation. Not knowing what the code is for, this is a viable alternative. – dav_i Sep 24 '13 at 12:10
maybe you are right, it depends ;) – Kamil Budziewski Sep 24 '13 at 12:11

Sorting List of String by their rank

2 Answers2