sorting of strings by position of another string

Question

What is the best way to do - Given a string A, and collection of strings C, order the strings in the collection in the non decreasing order of the position of A in the strings.

For instance,

A= abc
C= [deabc, abc, dabc, dad] 
Sorted C= [abc, dabc, deabc]

My idea is to iterate over the collection and put it in a HashMap/Dictionary with the position of A in C[i] as index. And then constructing the sorted collection from HashMap. This is not a homework problem. Just wanted to know the efficient way/algorithm of doing this. Any pointers will be helpful.

what about performance? if LINQ cannot be used, is there a efficient way to do this? — ABC
– ABC, Commented Jan 18, 2013 at 16:49

mellamokb · Accepted Answer · 2013-01-18 17:00:22Z

4

Here's a simple way with LINQ:

var SortedC = C.OrderBy (d => d.IndexOf(A)).ToArray();

Note that strings not containing A will be sorted at the beginning because IndexOf returns -1. Also, the behavior for strings with A at the same index is undefined, and will be returned in arbitrary order unless you provide a .ThenBy sort to handle those.

edited Jan 18, 2013 at 17:00

answered Jan 18, 2013 at 16:47

mellamokb

56.8k12 gold badges111 silver badges138 bronze badges

Sign up to request clarification or add additional context in comments.

4 Comments

Ilya Ivanov Over a year ago

maybe you mean d.IndexOf(a) ?

digEmAll Over a year ago

If the strings are long maybe could be convenient to do: var sorted = C.Select(x => new {Str=x,Pos=x.IndexOf(A)}).OrderBy(x => x.Pos).Select(x => x.Str);

ABC Over a year ago

@mellamokb, is there a way to filter -1 values (a not found in d) in the order by clause?

mellamokb Over a year ago

Do you want to leave them out entirely? If so, do C.Where(d => d.IndexOf(A) != -1).OrderBy...

Tommaso Belluzzo · Accepted Answer · 2013-01-18 16:48:15Z

1

stringsArray.OrderBy(s => s.IndexOf("a"))

answered Jan 18, 2013 at 16:48

Tommaso Belluzzo

23.7k8 gold badges77 silver badges102 bronze badges

Collectives™ on Stack Overflow

sorting of strings by position of another string

2 Answers 2

4 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

4 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related