Filtering 2 lists in a performant way

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0
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I have 2 lists:

newUpdates and updatesToAdd

I first of all need to remove all the occurrences of updatesToAdd from the newUpdates list by their Id. Then I need to add all updatesToAdd back into newUpdates to prevent duplicates.

It may not be clear why I'm doing this, but I need to swap out multiple occurrences of items that share the same Id (different update type) to then reinsert just one item for that Id with a main/master/catch all update type.

The code I have so far does this, but it runs very slowly. Is there a more performant way to write this?

    var newUpdates = new List<Entity>();

    var updatesToAdd = new List<Entity>();



    var Ids = updatesToAdd.Select(x => x.Id).ToList();

    newUpdates.RemoveAll(x => Ids.Contains(x.Id));

    newUpdates.AddRange(updatesToAdd);

I tried doing:

    newUpdates.Union(updatesToAdd).ToList();

However, I still ended up with duplicates in my list.

edited Nov 22 at 18:02

Uwe Keim

27.3k30128210

asked Nov 22 at 17:13

Dave

606

1

Use a HashSet for Ids. Solves both your performance and duplicates issue.
– Funk
Nov 22 at 17:22

add a comment |

up vote
0
down vote

favorite

I have 2 lists:

newUpdates and updatesToAdd

I first of all need to remove all the occurrences of updatesToAdd from the newUpdates list by their Id. Then I need to add all updatesToAdd back into newUpdates to prevent duplicates.

The code I have so far does this, but it runs very slowly. Is there a more performant way to write this?

    var newUpdates = new List<Entity>();

    var updatesToAdd = new List<Entity>();



    var Ids = updatesToAdd.Select(x => x.Id).ToList();

    newUpdates.RemoveAll(x => Ids.Contains(x.Id));

    newUpdates.AddRange(updatesToAdd);

I tried doing:

    newUpdates.Union(updatesToAdd).ToList();

However, I still ended up with duplicates in my list.

edited Nov 22 at 18:02

Uwe Keim

27.3k30128210

asked Nov 22 at 17:13

Dave

606

1

Use a HashSet for Ids. Solves both your performance and duplicates issue.
– Funk
Nov 22 at 17:22

add a comment |

up vote
0
down vote

favorite

I have 2 lists:

newUpdates and updatesToAdd

I first of all need to remove all the occurrences of updatesToAdd from the newUpdates list by their Id. Then I need to add all updatesToAdd back into newUpdates to prevent duplicates.

The code I have so far does this, but it runs very slowly. Is there a more performant way to write this?

    var newUpdates = new List<Entity>();

    var updatesToAdd = new List<Entity>();



    var Ids = updatesToAdd.Select(x => x.Id).ToList();

    newUpdates.RemoveAll(x => Ids.Contains(x.Id));

    newUpdates.AddRange(updatesToAdd);

I tried doing:

    newUpdates.Union(updatesToAdd).ToList();

However, I still ended up with duplicates in my list.

edited Nov 22 at 18:02

Uwe Keim

27.3k30128210

asked Nov 22 at 17:13

Dave

606

I have 2 lists:

newUpdates and updatesToAdd

I first of all need to remove all the occurrences of updatesToAdd from the newUpdates list by their Id. Then I need to add all updatesToAdd back into newUpdates to prevent duplicates.

The code I have so far does this, but it runs very slowly. Is there a more performant way to write this?

    var newUpdates = new List<Entity>();

    var updatesToAdd = new List<Entity>();



    var Ids = updatesToAdd.Select(x => x.Id).ToList();

    newUpdates.RemoveAll(x => Ids.Contains(x.Id));

    newUpdates.AddRange(updatesToAdd);

I tried doing:

    newUpdates.Union(updatesToAdd).ToList();

However, I still ended up with duplicates in my list.

c# linq

edited Nov 22 at 18:02

Uwe Keim

27.3k30128210

asked Nov 22 at 17:13

Dave

606

edited Nov 22 at 18:02

Uwe Keim

27.3k30128210

asked Nov 22 at 17:13

Dave

606

edited Nov 22 at 18:02

Uwe Keim

27.3k30128210

edited Nov 22 at 18:02

Uwe Keim

27.3k30128210

edited Nov 22 at 18:02

Uwe Keim

27.3k30128210

asked Nov 22 at 17:13

Dave

606

asked Nov 22 at 17:13

Dave

606

asked Nov 22 at 17:13

Dave

606

1

Use a HashSet for Ids. Solves both your performance and duplicates issue.
– Funk
Nov 22 at 17:22

add a comment |

1

Use a HashSet for Ids. Solves both your performance and duplicates issue.
– Funk
Nov 22 at 17:22

Use a HashSet for Ids. Solves both your performance and duplicates issue.
– Funk
Nov 22 at 17:22

add a comment |

1 Answer
1

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votes

up vote
1
down vote

Why not use Except instead?
https://docs.microsoft.com/en-us/dotnet/api/system.linq.enumerable.except?view=netframework-4.7.2

or Contains is false.

In fact I think you have a bug. I think you want to do this:

var newUpdates = new List<Entity>(); //overall list to add

var updatesToAdd = new List<Entity>();  //later list to add



var Ids = updatesToAdd.Select(x => x.Id).ToList();  //this line chagned

newUpdates.RemoveAll(x => Ids.Contains(x.Id));

newUpdates.AddRange(updatesToAdd);

edited Nov 22 at 17:33

answered Nov 22 at 17:24

Jeff Davies

458411

add a comment |

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1 Answer
1

active

oldest

votes

1 Answer
1

active

oldest

votes

up vote
1
down vote

Why not use Except instead?
https://docs.microsoft.com/en-us/dotnet/api/system.linq.enumerable.except?view=netframework-4.7.2

or Contains is false.

In fact I think you have a bug. I think you want to do this:

var newUpdates = new List<Entity>(); //overall list to add

var updatesToAdd = new List<Entity>();  //later list to add



var Ids = updatesToAdd.Select(x => x.Id).ToList();  //this line chagned

newUpdates.RemoveAll(x => Ids.Contains(x.Id));

newUpdates.AddRange(updatesToAdd);

edited Nov 22 at 17:33

answered Nov 22 at 17:24

Jeff Davies

458411

add a comment |

up vote
1
down vote

Why not use Except instead?
https://docs.microsoft.com/en-us/dotnet/api/system.linq.enumerable.except?view=netframework-4.7.2

or Contains is false.

In fact I think you have a bug. I think you want to do this:

var newUpdates = new List<Entity>(); //overall list to add

var updatesToAdd = new List<Entity>();  //later list to add



var Ids = updatesToAdd.Select(x => x.Id).ToList();  //this line chagned

newUpdates.RemoveAll(x => Ids.Contains(x.Id));

newUpdates.AddRange(updatesToAdd);

edited Nov 22 at 17:33

answered Nov 22 at 17:24

Jeff Davies

458411

add a comment |

up vote
1
down vote

Why not use Except instead?
https://docs.microsoft.com/en-us/dotnet/api/system.linq.enumerable.except?view=netframework-4.7.2

or Contains is false.

In fact I think you have a bug. I think you want to do this:

var newUpdates = new List<Entity>(); //overall list to add

var updatesToAdd = new List<Entity>();  //later list to add



var Ids = updatesToAdd.Select(x => x.Id).ToList();  //this line chagned

newUpdates.RemoveAll(x => Ids.Contains(x.Id));

newUpdates.AddRange(updatesToAdd);

edited Nov 22 at 17:33

answered Nov 22 at 17:24

Jeff Davies

458411

Why not use Except instead?
https://docs.microsoft.com/en-us/dotnet/api/system.linq.enumerable.except?view=netframework-4.7.2

or Contains is false.

In fact I think you have a bug. I think you want to do this:

var newUpdates = new List<Entity>(); //overall list to add

var updatesToAdd = new List<Entity>();  //later list to add



var Ids = updatesToAdd.Select(x => x.Id).ToList();  //this line chagned

newUpdates.RemoveAll(x => Ids.Contains(x.Id));

newUpdates.AddRange(updatesToAdd);

edited Nov 22 at 17:33

answered Nov 22 at 17:24

Jeff Davies

458411

edited Nov 22 at 17:33

answered Nov 22 at 17:24

Jeff Davies

458411

answered Nov 22 at 17:24

Jeff Davies

458411

answered Nov 22 at 17:24

Jeff Davies

458411

add a comment |

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