Sort a list of strings which contains float numbers

Question

I have a list of object which contains a field Number. This field is a string that includes float numbers: 0.5, 0.2, 10.0, 2.2, 2.1, 1.1, 1.0, 2.12, 1.14. I want this list sorted (descendent) based on this Number so I have this output: 10.0, 2.2, 2.12, 2.1, 1.14, 1.1, 1.0, 0.5, 0.2.

I have tried to do this:

List<MyObject> sortedList = myUnsortedList.OrderyDescending(x => x.Number).ToList();

Also, I have tried to use PadLeft like this (as this user suggested https://stackoverflow.com/a/6396523/3872144):

int maxlen = myUnsortedList.Max(x => x.Number.Length);

List<MyObject> sortedList = myUnsortedList.OrderyDescending(x => x.Number.PadLeft(maxlen, '0'));

But in both cases I got wrong results like: 2.12, 10.0, 2.2, 2.1, 1.14, 1.1, 1.0, 0.5, 0.2.

Do you have any idea how to solve this issue?

Just order by thier casted(double) value – sagi Apr 05 '21 at 14:05 — sagi, Apr 05 '21 at 14:05
yes, solved my issues. Thank you – ghostlegend Apr 06 '21 at 10:32 — ghostlegend, Apr 06 '21 at 10:32

Tim Schmelter · Accepted Answer · 2021-04-05T14:09:28.963

5

The question arises why you have a string in the first place if you store a double. You should parse them as soon as possible (or prevent that they are strings where you load them).

However, you can always try to parse them afterwards:

List<MyObject> sortedList = myUnsortedList
    .OrderyDescending(x => double.Parse(x.Number))
    .ToList();

If you dont know if they have all a valid format you can use double.TryParse. Maybe you need to pass the appropriate CultureInfo to double.Parse(for example if your current culture uses comma as decimal separator).

edited Apr 05 '21 at 14:09

answered Apr 05 '21 at 14:03

Tim Schmelter

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That's what I needed. For some reasons I cannot change de type, but it works properly with the Parse. Thank you! – ghostlegend Apr 06 '21 at 10:33

Sort a list of strings which contains float numbers

1 Answers1