C#: Combine two elements of the SAME list (no duplicates)-CodePudding

I have a list of objects.

These objects have among other elements one string called "reference". The list might look like this:

|reference| description |
|123      | this should |
|124      | sth         |
|125      | sth         |
|123      | be one      |

I want to combine WITHIN this list all elements with the same reference. Result should be:

|reference| description       |
|123      | this should be one|
|124      | sth               |
|125      | sth               |

into a new list. So far I could only find solutions on how to group or how to combine two lists. Any ideas?

CodePudding user response：

You should group them according to reference field and concatenate the descriptions.

Something like this should work

var results = list
              .GroupBy(i => i.Reference)
              .Select(g => 
                  (Reference: g.Key, 
                   Description: string.Join(" ", g
                       .Select(i => i.Description)));

CodePudding user response：

Depending on your needs you can use an anonymous object or generate a new list of the type of yourclass...

void Main()
{
    var list = new List<YourClass>()
    {
        new YourClass{Reference = 123, Description = "this should"},
        new YourClass{Reference = 124, Description = "sth"},
        new YourClass{Reference = 125, Description = "sth"},
        new YourClass{Reference = 123, Description = "be one"},
    };
    
    var combined = list
        .GroupBy(item => item.Reference)
        .Select(group => new YourClass
        {
            Reference = group.Key, 
            Description = string.Join(" ", group.Select(element => element.Description))
        });
        
    Console.WriteLine(combined);
}

class YourClass
{
    public int Reference {get;set;}
    public string Description {get;set;}
}