Correct way for sorting a String array

Question

System.Collections.Generic.IEnumerable<String> lines = File.ReadLines("K:\\file.txt");

The file contains the following data

1
2
3
99
32
HR210
Redmond City Room A
23
Telephone Conference
HR252

Each line has 1 entry which represents a room in a building.

How do I sort it numerically and alphabetically. So my results look like

1
2
3
23
32
99
HR210
HR252
Redmond City Room A
Telephone Conference

The alphabetical part comes after the numbers.

Will you have any strings that _start_ with a number but contain alpha characters afterwards? (e.g. `123ABC`). If so how should those be sorted? — D Stanley, Apr 07 '14 at 15:40
take a look at natural comparer: http://stackoverflow.com/questions/8568696/icomparer-for-natural-sorting — Fabian Bigler, Apr 07 '14 at 15:42

score 4 · Accepted Answer · answered Apr 07 '14 at 15:38

You could use int.TryParse and an anonymous type + Enumerable.OrderBy:

int i;
lines = lines
    .Select(l => new { Line = l, IsText = !int.TryParse(l, out i), Value = i })
    .OrderBy(x => x.IsText)
    .ThenBy(x => x.Value).ThenBy(x => x.Line)
    .Select(x => x.Line);

.OrderBy(x => x.IsText) returns a bool where true is "higher" than false. That's why all text-lines come last.

score 0 · Answer 2 · edited May 23 '17 at 12:26

0

You'll want to implement your own IComparer. You can use this method to easily create it, using built in functions. If you must write it yourself, Tim's answer will give you what you want.

edited May 23 '17 at 12:26

Community

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answered Apr 07 '14 at 15:40

Kyle W

3,702
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score 0 · Answer 3 · edited May 23 '17 at 10:33

0

Take a look at Natural Comparing.

IComparer for natural sorting

http://www.codeproject.com/Articles/22517/Natural-Sort-Comparer

edited May 23 '17 at 10:33

Community

1
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answered Apr 07 '14 at 15:43

Fabian Bigler

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Correct way for sorting a String array

3 Answers3