Find if a Substring is Part of List/Array Directly

Question

I've a list defined as:

List<string> content = new List<string>(){ "Hello This", "This is", "This" };

I want a code to find if the list contains the Keyword This, and if yes get its first occurrence.

Existing Code :

foreach(string line in content){
     if(line.Contains("This"))
          return line;
}

I want to simply and know if some other alternative is there. If we know the complete string then we could use List.Contains, but for a substring, how to proceed?

USING .NET 2.0. Please suggest without using LINQ.

@DGibbs nothing is wrong but I wanted to know if there's something more simple/direct I could be using instead of this. — B V Raman
– B V Raman, Commented May 10, 2016 at 9:57
@B V Raman It looks perfectly simple to me. If I couldn't use LINQ, that's how I'd do it. Only thing I'd suggest is making sure you're doing a case-insensitive comparison/contains — DGibbs
– DGibbs, Commented May 10, 2016 at 9:59
Which version of C#? Multiple answers use lambda expressions, but those didn't exist prior to C# 3, which was introduced after .NET 2.0. — Jeroen Mostert
– Jeroen Mostert, Commented May 10, 2016 at 10:22

M.S. · Accepted Answer · 2016-05-10 10:15:28Z

2

As mentioned on MSDN, FindIndex is available since Framework 2.0 and can be used for your problem.

FindIndex searches for an element that matches the conditions defined by the specified predicate, and returns the zero-based index of the first occurrence within the entire List.

List<string> content = new List<string>() { "Hello This", "This is", "This" };
var index = content.FindIndex(p => p.Contains("This"));
if (index >= 0)
    return content[index];

edited May 10, 2016 at 10:15

answered May 10, 2016 at 10:09

M.S.

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Comments

Master DJon · Accepted Answer · 2016-05-12 05:12:54Z

1

Here is what you were searching for in C#2.0 :

List<string> content = new List<string>() { "Hello This", "This is", "This" };
string keyword = "This";
string element = content.Find(delegate(string s) { return s.Contains(keyword); });

answered May 12, 2016 at 5:12

Master DJon

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Comments

Eldho · Accepted Answer · 2016-05-10 10:29:52Z

0

Find() The first element that matches the conditions defined by the specified predicate, if found; otherwise, the default value for type T Msdn

Find() is available from NET Framework 2.0

 List<string> content = new List<string>() { "Hello This", "This is", "This" };
 string firstOccurance = content.Find(g => g.Contains("This"));

edited May 10, 2016 at 10:29

answered May 10, 2016 at 10:16

Eldho

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Comments

Carra · Accepted Answer · 2016-05-10 09:53:18Z

-1

You could use linq, this will do the same as your for loop:

return content.FirstOrDefault(x => x.Contains("This"));

edited May 10, 2016 at 9:53

answered May 10, 2016 at 9:52

Carra

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3 Comments

RB. Over a year ago

He will want FirstOrDefault as he doesn't know the list contains the item he is searching for...

B V Raman Over a year ago

Thanks, but any approach without LINQ since I'm on .NET 2.0

Nimesh Gami Over a year ago

Carra - its linq "FirstOrDefault" and "Contains".

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