Filter list<string> using linq

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Hi,
I want to filter string list based on some condition as given below,

List<string> config = new List<string>();
               config.Add("userdata.member1");
               config.Add("userdata.member2");
               config.Add("userdata.member3");
               config.Add("userdata.member4");
               config.Add("userdata.member5");
               config.Add("attribute.memberattribute1");
               config.Add("attribute.memberattribute2");
               config.Add("attribute.memberattribute3");
               config.Add("attribute.memberattribute4");
               config.Add("attribute.memberattribute5");

               string[] userDataKeys = config.Select(x => x.Contains("userdata.")?x.Replace("userdata.",""):x).ToArray();

What I have tried:

I want to check whether the string has "userdata." and replace it with empty string finally return the replaced items only.

Expected output:
member1
member2
member3
member4
member5

can anyone tell me how to achieve it using linq.

Thanks.

Posted 13-Oct-17 0:03am

Member 10281805

Updated 13-Oct-17 3:26am

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3 solutions

Solution 3

There's no need to use .StartWith or .Contains method. Simple .Replace should be enough :)

C#

var result = config.Select(x=>x.Replace("userdata.", string.Empty)).ToList();

Of course, if you want to return only data with member word, you can use:

C#

var result = config.Where(x=>x.Contains("member")).Select(x=>x.Replace("userdata.", string.Empty)).ToList();

Posted 13-Oct-17 3:26am

Maciej Los

Updated 13-Oct-17 3:29am

v2

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Pete O'Hanlon · Accepted Answer · 2017-10-13T00:30:00

Solution 1

You're almost there. First you need to identify which records contain userdata.. A where clause helps here:

C#

config.Where(x => x.StartsWith("userdata.")).Select(x => x.Replace("userdata.", string.Empty)).ToList();

Posted 13-Oct-17 0:30am

Pete O'Hanlon

Comments

Maciej Los 13-Oct-17 9:26am

5ed!
Note: there's no need to use .StartWith or .Contains method. Simple .Replace should be enough. Check my answer.

Pete O'Hanlon 13-Oct-17 10:04am

If the user was only looking to replace the string, then Replace would be enough; as they also wanted to return the list of records that they changed, the list has to be filtered first - hence the Where clause using StartsWith.

Karthik_Mahalingam · Accepted Answer · 2017-10-13T00:31:00

Solution 2

try

string[] userDataKeys = config.Where(x => x.Contains("userdata.")).Select(x => x.Replace("userdata.", "") ).ToArray();

Posted 13-Oct-17 0:31am

Karthik_Mahalingam

Comments

Maciej Los 13-Oct-17 9:26am

5ed!
Note: there's no need to use .StartWith or .Contains method. Simple .Replace should be enough. Check my answer.

Karthik_Mahalingam 13-Oct-17 9:38am

Thank you Maciej

but the Op's
Expected output is
member1
member2
member3
member4
member5

Maciej Los 13-Oct-17 9:49am

I know, that's why my second part of answer meets OP's criteria ;)

Karthik_Mahalingam 13-Oct-17 10:38am

:)counter 5!

Maciej Los 13-Oct-17 12:45pm

Thank you, Karthik