Find substring in a list of strings

Question

I have a list like so and I want to be able to search within this list for a substring coming from another string. Example:

List<string> list = new List<string>();
string srch = "There";
list.Add("1234 - Hello");
list.Add("4234 - There");
list.Add("2342 - World");

I want to search for "There" within my list and return "4234 - There". I've tried:

var mySearch = list.FindAll(S => s.substring(srch));
foreach(var temp in mySearch)
{
    string result = temp;
}

BrokenGlass · Accepted Answer · 2012-05-07T20:37:48.617

33

With Linq, just retrieving the first result:

string result = list.FirstOrDefault(s => s.Contains(srch));

To do this w/o Linq (e.g. for earlier .NET version such as .NET 2.0) you can use List<T>'s FindAll method, which in this case would return all items in the list that contain the search term:

var resultList = list.FindAll(delegate(string s) { return s.Contains(srch); });

edited May 07 '12 at 20:37

answered May 07 '12 at 20:25

BrokenGlass

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Hi, thanks for the quick answer, I'm getting a compile error: FirstOrDefault and not extension method. Do I need to add sometype of list library? – user1380621 May 07 '12 at 20:30
How to add Linq? Sorry for newby question. – user1380621 May 07 '12 at 20:34
2

you need to add a `using System.Linq` to your file - I assume you are using .NET 4.0 ? – BrokenGlass May 07 '12 at 20:34
My project was set to 2.0, I changed to 4.0 but now its a big mess of compile errors. Was able to add System.Linq however. Thanks guys. – user1380621 May 07 '12 at 20:39
2

Of course you can also use the short form (`s => s.Contains(srch)`) for `FindAll`. – d4Rk Mar 10 '16 at 14:12
Whats about 'IgnoreCase' ? – Diego Venâncio Apr 16 '19 at 13:49

score 13 · Answer 2 · answered May 07 '12 at 20:25

13

To return all th entries:

IEnumerable<string> result = list.Where(s => s.Contains(search));

Only the first one:

string result = list.FirstOrDefault(s => s.Contains(search));

answered May 07 '12 at 20:25

abatishchev

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This 'where' doesnt work, returns empty List. The selected answer do the job. – Jhollman Jul 20 '20 at 13:54
@Jhollman: nope, it works fine https://dotnetfiddle.net/bjuZ5p Check your code, you might ran into a casing issue. Feel free to ask a new question. – abatishchev Jul 23 '20 at 16:12

score 1 · Answer 3 · answered May 07 '12 at 20:34

What you've written causes the compile error

The best overloaded method match for 'string.Substring(int)' has some invalid arguments

Substring is used to get part of string using character position and/or length of the resultant string.

for example srch.Substring(1, 3) returns the string "her"

As other have mentioned you should use Contains which tells you if one string occurs within another. If you wanted to know the actual position you'd use IndexOf

score 1 · Answer 4 · edited Oct 27 '13 at 08:25

1

same problem i had to do.

You need this:

myList.Where(listStrinEntry => myString.IndexOf(listStringEntry) != -1)

Where:

myList is List<String> has the values that myString has to contain at any position

So de facto you search if myString contains any of the entries from the list. Hope this is what you wanted...

edited Oct 27 '13 at 08:25

Harry

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answered Oct 27 '13 at 08:05

a joka

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score 0 · Answer 5 · answered May 07 '12 at 20:44

0

i like to use indexOf or contains

someString.IndexOf("this");
someString.Contains("this");

answered May 07 '12 at 20:44

unarity

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score 0 · Answer 6 · answered Apr 16 '19 at 14:05

0

And for CaseSensitive use:

YourObj yourobj = list.FirstOrDefault(obj => obj.SomeString.ToLower().Contains("some substring"));

OR

YourObj yourobj = list.FirstOrDefault(obj => obj.SomeString.ToUpper().Contains("some substring"));

answered Apr 16 '19 at 14:05

Diego Venâncio

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Find substring in a list of strings

6 Answers6

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