Remove item from list based on condition

C#.NetEntity FrameworkLinq

C# Problem Overview


I have a struct like this:

public struct stuff
{
    public int ID;
    public int quan;
}

and want to to remove the product where ID is 1.
I'm trying this currently:

prods.Remove(new stuff{ prodID = 1});

and it's not working.

THANKS TO ALL

C# Solutions


Solution 1 - C#

If your collection type is a List<stuff>, then the best approach is probably the following:

prods.RemoveAll(s => s.ID == 1)

This only does one pass (iteration) over the list, so should be more efficient than other methods.

If your type is more generically an ICollection<T>, it might help to write a short extension method if you care about performance. If not, then you'd probably get away with using LINQ (calling Where or Single).

Solution 2 - C#

Using linq:

prods.Remove( prods.Single( s => s.ID == 1 ) );

Maybe you even want to use SingleOrDefault() and check if the element exists at all ...

EDIT:
Since stuff is a struct, SingleOrDefault() will not return null. But it will return default( stuff ), which will have an ID of 0. When you don't have an ID of 0 for your normal stuff-objects you can query for this ID:

var stuffToRemove = prods.SingleOrDefault( s => s.ID == 1 );
if( stuffToRemove.ID != 0 )
{
    prods.Remove( stuffToRemove );
}

Solution 3 - C#

If you have LINQ:

var itemtoremove = prods.Where(item => item.ID == 1).First();
prods.Remove(itemtoremove)

Solution 4 - C#

prods.Remove(prods.Find(x => x.ID == 1));

Solution 5 - C#

Here is a solution for those, who want to remove it from the database with Entity Framework:

prods.RemoveWhere(s => s.ID == 1);

And the extension method itself:

using System;
using System.Linq;
using System.Linq.Expressions;
using Microsoft.EntityFrameworkCore;

namespace LivaNova.NGPDM.Client.Services.Data.Extensions
{
    public static class DbSetExtensions
    {
        public static void RemoveWhere<TEntity>(this DbSet<TEntity> entities, Expression<Func<TEntity, bool>> predicate) where TEntity : class
        {
            var records = entities
                .Where(predicate)
                .ToList();
            if (records.Count > 0)
                entities.RemoveRange(records);
        }
    }
}

P.S. This simulates the method RemoveAll() that's not available for DB sets of the entity framework.

Solution 6 - C#

You can only remove something you have a reference to. So you will have to search the entire list:

stuff r;
foreach(stuff s in prods) {
  if(s.ID == 1) {
      r = s;
      break;
  }
}
prods.Remove(r);

or

for(int i = 0; i < prods.Length; i++) {
    if(prods[i].ID == 1) {
        prods.RemoveAt(i);
        break;
    }
}

Solution 7 - C#

prods.Remove(prods.Single(p=>p.ID == 1));

you can't modify collection in foreach, as Vincent suggests

Solution 8 - C#

You could use Linq.

var prod = from p in prods
           where p.ID != 1
           select p;

Attributions

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Content TypeOriginal AuthorOriginal Content on Stackoverflow
QuestionDELETE meView Question on Stackoverflow
Solution 1 - C#NoldorinView Answer on Stackoverflow
Solution 2 - C#tanasciusView Answer on Stackoverflow
Solution 3 - C#Nathan WView Answer on Stackoverflow
Solution 4 - C#AlexView Answer on Stackoverflow
Solution 5 - C#Just ShadowView Answer on Stackoverflow
Solution 6 - C#Vincent McNabbView Answer on Stackoverflow
Solution 7 - C#KikaimaruView Answer on Stackoverflow
Solution 8 - C#ChrisView Answer on Stackoverflow