How to check if a string is contained in another list of strings?

Question

I have a list of folders in which I contain a list of languages that I want to be processed:

eng_US
spa_ES

etc...

I have a list of directories containing subfolders for each language it has. They can be more than the ones defined in my languages list. It can look like this:

ja-JP
eng_US
spa_Es
fr_FR

I list the directories in that specific folder like this:

string[] directories = Directory.GetDirectories(path);

I want to get with Linq all that folders that are inside my private language list.

I tried something similar to this:

string[] directories = Directory.GetDirectories(path).Where(x => x.Contains(languageList.Value));

But, obviously is bad :(

How can I get only the folders which are also listed in my private language list?

So, how can I check if my resulting path is contained inside another string list with Linq?

Thanks!

NOTE: My language list is saved in a Dictionary.

IDictionary<int, string> languages;

Because it's not working and it's badly formatted. It doesn't even compile. I'm trying to use logic with Lynq, but not working... — Sonhja, Jun 13 '16 at 14:42
Possible duplicate of [Does .NET have a way to check if List a contains all items in List b?](http://stackoverflow.com/questions/1520642/does-net-have-a-way-to-check-if-list-a-contains-all-items-in-list-b) — Thomas Ayoub, Jun 13 '16 at 14:49
It looks like that, but don't understand how to apply it... I'm using .Net 4.5 — Sonhja, Jun 13 '16 at 14:51
If you want to check (get a boolean result), there is a good answer below. However, if you want to get the intersection of two string lists, you should use exactly that: [Intersect](https://msdn.microsoft.com/en-us/library/bb460136(v=vs.100).aspx) — grek40, Jun 13 '16 at 15:02

John Bustos · Accepted Answer · 2016-06-13T14:58:18.833

1

You're pretty close - Remember languageList is a list of names you care about and your Linq statement will return one string value at a time to put through your Where clause, so you'd want it to look as follows:

string[] directories = Directory.GetDirectories(path).Where(x => languageList.Contains(x)).ToArray();

Basically saying Give me back and returned value that is contained in languageList

Hope that makes sense.

edited Jun 13 '16 at 14:58

answered Jun 13 '16 at 14:55

John Bustos

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Don't fall into his trap... `Where(...)` doesn't return `string[]` type – grek40 Jun 13 '16 at 14:57
Don¡t worry! That was excatly! I returned a List :D – Sonhja Jun 13 '16 at 14:58
Glad it gave you what you needed! – John Bustos Jun 13 '16 at 14:59

score 0 · Answer 2 · answered Jun 13 '16 at 14:57

You need to compare on the directory name not the full path. Also you are checking if the directory path contains a value gotten from language list.

string[] directories = Directory.GetDirectories(path)
                                .Where(d => languageList.Contains(Path.GetFileName(d)))
                                .ToArray();

Note that you have to use Path.GetFileName as this will return 'endfolder' from 'C:\folder\endfolder'. Whereas Path.GetDirectoryName will return 'C:\folder'.

How to check if a string is contained in another list of strings?

2 Answers2