LINQ extension methods are used to perform queries on the lists and collections.We can use C# for the LINQ queries rather using any other language such as SQL.
We can Compare List elements in C# using LINQ ,by using the extension methods.
To compare lists using LINQ there is a SequenceEqual extension method provided by the framework.If we have two arrays arr1 and arr2 declared as:
string[] arr1 = { "A", "B", "C" }; string[] arr2 = { "A", "B", "C" };then we can compare the above arrays using the SequenceEqual[] method as:
bool result = arr3.SequenceEqual[arr2];The result variable will contain the value true as arr1 and arr2 contains the same elements.
Instead of arrays we can compare two lists using the SequenceEqual[] method.So if there are two lists of strings declared as:
List arr4 = new List[]{ "A", "B", "C" }; List arr5 = new List[] { "A", "B", "C" };then we can compare them as:
bool result = arr4.SequenceEqual[arr5];result will still have the value true since the two lists are identical.Above we are comparing two generic lists of strings.
But there is an important point to consider:
When using SequenceEqual to compare two lists or arrays ,the items in the two collections should be the same in the same ordinal.For example if the first list contains the value “A” in the first position then the second list should also contain the value “A” in the first position.
Though to compare List elements in C# using LINQ the framework provides the SequenceEqual method.This method compares elements based on the ordinal.We can implement logic to compare elements independent of the ordinals.
So if we now have two arrays with the same values but in different positions then SequenceEqual will return the value false.
string[] arr2 = { "A", "B", "C" }; string[] arr3 = { "B", "C", "A"}; bool result = arr2.SequenceEqual[arr3];The result of the above comparison will return false.
So as evident we need to use some different approach to compare the List elements in C# using LINQ.
To compare collections which may contain same values but in different positions we can use custom logic.Here we will use the LINQ extension methods for comparing the two collections.
If two collections contains the same elements then the following two points will be true:
- The size of two collections will be same
- Each collection will contain the element of the other collection
We can implement logic to verify these using LINQ as:
Here we are checking if arr2 contains every element of arr3 and if the size of two collections is same.We can call the above method as:
string[] arr2 = { "A", "B", "C" }; string[] arr3 = { "B", "C", "A"}; bool result=ComapreLists[arr2, arr3];CompareLists method above will return true if the two passed array arguments contains the same elements.
So we can easily implement the method to Compare List elements in C# using LINQ.If we don’t use LINQ then our logic will be more complicated.
We can Compare List elements in C# using LINQ ,by using the extension methods. To compare lists using LINQ there is a SequenceEqual extension method provided by the framework. If we have two arrays arr1 and arr2 declared as: string[] arr1 = { “A”, “B”, “C” }; string[] arr2 = { “A”, “B”, “C” }; If you have lists of objects and want to get the common objects for some property then use; var commons = TestList1. Select[s1 => s1. SomeProperty]. Remarks. The SequenceEqual[IEnumerable, IEnumerable] method enumerates the two source sequences in parallel and compares corresponding elements by using the default equality comparer for TSource , Default. The default equality comparer, Default, is used to compare values of the types. To find the duplicate values only : var duplicates = list. GroupBy[x => x. Key]. Any[g => g. reduce[] function to compare the data items of two lists. The map[] method accepts a function and an iterable such as list, tuple, string, etc. as arguments. It applies the passed function to each item of the iterable and then returns a map object i.e. an iterator as the result. Parallel LINQ [PLINQ] is a parallel implementation of the Language-Integrated Query [LINQ] pattern. PLINQ implements the full set of LINQ standard query operators as extension methods for the System. PLINQ combines the simplicity and readability of LINQ syntax with the power of parallel programming. Linq, acts upon 2 collections. It returns a new collection that contains the elements that are found. Union removes duplicates. So this method can be thought of as two actions: it combines the two collections and then uses Distinct[] on them, removing duplicate elements. You can check the equality of strings using two ways: Using == operator. Using Equals[] method….== vs Equals. Clone a List in C# An IGrouping is an IEnumerable that additionally has a key. The key represents the attribute that is common to each value in the IGrouping. The values of an IGrouping are accessed much as the elements of an IEnumerable are accessed. DataTable dt = new DataTable[]; dt. Rows. Add[2,Test1,Sample1]; dt. Now e2 is an IEnumerable and can work with all LINQ functions. You can also use LINQ’s query comprehension syntax, which casts to the type of the range variable [ item in this example] if a type is specified: The effect is identical to @JaredPar’s solution; see 7.16.2.2: Explicit Range Variable Types in the C# language specification for details. What is Linq Contains in C#? The Linq Contains Method in C# is used to check whether a sequence or collection [i.e. data source] contains a specified element or not. If the data source contains the specified element, then it returns true else return false. How to Get common data from two list in c#?
How to compare two IEnumerable string in c#?
How do I find duplicate records in Linq?
How do you compare two lists of strings?
What is Plinq in C#?
Does Union remove duplicates Linq?
How do you equal a string in C#?
==
Equals[]
Compares the content of strings.
Compares the content of strings.
How do I copy one list to another in C#?
What is IGrouping?
How can we find duplicate values in DataTable using Linq?
Can a LINQ function work with an IEnumerable?
When to use LINQ contains in C #?
When to return true else false in LINQ?
If any of the elements satisfy the given condition, then it returns true else return false. It is also used to check whether a collection contains some data or not. That means it checks the length of the collection also. If it contains any data then it returns true else return false.
How to compare the contents of two IEnumerables?
Rather than the two O [n log n] sorts of using OrderBy [] followed by the O [n] comparison, you’ve an O [n] operation building the set of tallies, and an O [n] check against it. Is this answer outdated? But that does only work correctly if the values are distinct. are also considered as “equal” with the mentioned method. Is this answer outdated?
How to filter two list in c# using LINQ?
LINQ filter: How to filter a list using another list with LINQ
- By Rod McBride.
- varfilter = new[] { “Action”, “Animation”, “Comedy”};
- GetMovies[]
- .Where[movie =>
- movie.Genre.Split[‘|’]
- .Select[arrayElement => arrayElement.Trim[]]
- .Any[value => filter.Contains[value]]]
- .Dump[];
How to compare two list Value in c#?
Equals[Object] Method which is inherited from the Object class is used to check if a specified List object is equal to another List object or not. Syntax: public virtual bool Equals [object obj]; Here, obj is the object which is to be compared with the current object.
How do you filter rows by list selection?
Run the Advanced Filter
- Select a cell in the data table.
- On the Data tab of the Ribbon, in the Sort & Filter group, click Advanced.
- For Action, select Filter the list, in-place.
- For List range, select the data table.
- For Criteria range, select C1:C2 – the criteria heading and formula cells.
- Click OK, to see the results.
Are two lists equal C#?
This post will discuss how to compare two lists in C#. Two lists are equivalent if they have the same elements in the same quantity but any order. Individual elements are equal if their values are equal, not if they refer to the same object.
How to filter a list using another list with LINQ?
I created the query below: Listing 1. LINQ query to filter the movies by selected genres First, I added a filter for the selected genres [a string array] in Figure 2. The GetMovies [] method returns a list of movies. In this case, it’s a just a small collection created within the method, but it could have been retrieved from a database.
How to compare two lists [ LINQ ] C #?
This example shows how to use LINQ to compare two lists of strings and output those lines that are in names1.txt but not in names2.txt. Copy names1.txt and names2.txt to your solution folder as shown in How to combine and compare string collections [LINQ] [C#].
Is the list1 and the list2 the same?
In your code, both the list have same class person. But in my scenario, List1 is person and List2 is generic list. Happy Coding ! Mark as Answer if it helps. One more thing, I dont want to return all the missing elements from List 2.
How to compare two List and return not matching items?
This will return all messages in MsgList which don’t have a matching ID in SentList. Be aware this will take up to m*n operations as it compares every MsgID in SentList to each in MsgList [“up to” because it will short-circuit when it does happen to match].
We can Compare List elements in C# using LINQ ,by using the extension methods. To compare lists using LINQ there is a SequenceEqual extension method provided by the framework. If we have two arrays arr1 and arr2 declared as: string[] arr1 = { “A”, “B”, “C” }; string[] arr2 = { “A”, “B”, “C” };
How to compare the two List in c#?
Equals[Object] Method which is inherited from the Object class is used to check if a specified List object is equal to another List object or not. Syntax: public virtual bool Equals [object obj]; Here, obj is the object which is to be compared with the current object.
How do you filter rows by list selection?
Run the Advanced Filter
- Select a cell in the data table.
- On the Data tab of the Ribbon, in the Sort & Filter group, click Advanced.
- For Action, select Filter the list, in-place.
- For List range, select the data table.
- For Criteria range, select C1:C2 – the criteria heading and formula cells.
- Click OK, to see the results.
Are two lists equal C#?
This post will discuss how to compare two lists in C#. Two lists are equivalent if they have the same elements in the same quantity but any order. Individual elements are equal if their values are equal, not if they refer to the same object.
How to compare two lists using LINQ-stack?
Join has the drawback that your results might be duplicated if widgets1 or widgets2 contains elements with the same TypeID more than one [which also applies to your original code, by the way]. The following will do exactly what you want: Return all elements from widgets1 for which an element with a corresponding TypeID exists in widgets2.
How to compare two List and get values from first list?
If anyone of them don’t exist in Second List, I want to return that item ID and ID Name. How Can I do this using LINQ ? Thanks for the reply. In your code, both the list have same class person.
Is the list1 and the list2 the same?
In your code, both the list have same class person. But in my scenario, List1 is person and List2 is generic list. Happy Coding ! Mark as Answer if it helps. One more thing, I dont want to return all the missing elements from List 2.
How to do LINQ query between two list objects?
But cannot manage to implement it on LINQ query. It sounds like you are trying to find all instances of ObjectB which have a code value present in any of the List values. If so try the following List listA = …; List listB = …; var all = listB.Where [b => listA.Any [a => a.code == b.code]];
How to filter two List in C# using LINQ?
LINQ filter: How to filter a list using another list with LINQ
- By Rod McBride.
- varfilter = new[] { “Action”, “Animation”, “Comedy”};
- GetMovies[]
- .Where[movie =>
- movie.Genre.Split[‘|’]
- .Select[arrayElement => arrayElement.Trim[]]
- .Any[value => filter.Contains[value]]]
- .Dump[];
How to compare the two List in C#?
How do I compare two Excel lists for differences?
To quickly highlight cells with different values in each individual row, you can use Excel’s Go To Special feature.
- Select the range of cells you want to compare.
- On the Home tab, go to Editing group, and click Find & Select > Go To Special… Then select Row differences and click the OK button.
How to compare two lists [ LINQ ] C #?
This example shows how to use LINQ to compare two lists of strings and output those lines that are in names1.txt but not in names2.txt. Copy names1.txt and names2.txt to your solution folder as shown in How to combine and compare string collections [LINQ] [C#].
Is there any other way to compare two lists via typeid?
I am using two foreach loops to compare the lists by TypeID to populate a third list. Is there any other way using LINQ to compare these two lists via the TypeID?
We can Compare List elements in C# using LINQ ,by using the extension methods. To compare lists using LINQ there is a SequenceEqual extension method provided by the framework. If we have two arrays arr1 and arr2 declared as: string[] arr1 = { “A”, “B”, “C” }; string[] arr2 = { “A”, “B”, “C” };
How to filter two list in c# using LINQ?
LINQ filter: How to filter a list using another list with LINQ
- By Rod McBride.
- varfilter = new[] { “Action”, “Animation”, “Comedy”};
- GetMovies[]
- .Where[movie =>
- movie.Genre.Split[‘|’]
- .Select[arrayElement => arrayElement.Trim[]]
- .Any[value => filter.Contains[value]]]
- .Dump[];
How to Get common data from two list in c#?
If you have lists of objects and want to get the common objects for some property then use; var commons = TestList1. Select[s1 => s1. SomeProperty].
What is Plinq in C#?
Parallel LINQ [PLINQ] is a parallel implementation of the Language-Integrated Query [LINQ] pattern. PLINQ implements the full set of LINQ standard query operators as extension methods for the System. PLINQ combines the simplicity and readability of LINQ syntax with the power of parallel programming.
How to compare two lists [ LINQ ] C #?
This example shows how to use LINQ to compare two lists of strings and output those lines that are in names1.txt but not in names2.txt. Copy names1.txt and names2.txt to your solution folder as shown in How to combine and compare string collections [LINQ] [C#].
How to compare two List and get values from first list?
If anyone of them don’t exist in Second List, I want to return that item ID and ID Name. How Can I do this using LINQ ? Thanks for the reply. In your code, both the list have same class person.
How to filter a list using another list with LINQ?
I created the query below: Listing 1. LINQ query to filter the movies by selected genres First, I added a filter for the selected genres [a string array] in Figure 2. The GetMovies [] method returns a list of movies. In this case, it’s a just a small collection created within the method, but it could have been retrieved from a database.
How to use equality comparer in LINQ stack?
Simply have that equality comparer base equality only on MsgID property of each respective type. Since the equality comparer compares two instances of the same type, you would need to define an interface or common base type that both Sent and Messages implement that has a MsgID property.