C# | How to check whether a List contains a specified element - GeeksforGeeks (2024)

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C# | How to check whether a List contains a specified element - GeeksforGeeks? ›

List<T>. Contains(T) Method is used to check whether an element is in the List<T> or not.

Using the 'count()' Method

The 'count()' method allows you to count the occurrences of an element in a Python list. By checking if the count is greater than zero, you can determine if the element exists in the given list.

Syntax. public bool Contains (T value); It takes the T value as input, to be searched in the linked list. It returns true if the value is present in the linked list and false otherwise.

A- You can check if an array contains a specific element in C# by using the Contains() method provided by the System. Linq namespace.

public bool Contains (T item); Here, item is the object which is to be locate in the List<T>. The value can be null for reference types. Return Value: This method returns True if the item is found in the List<T> otherwise returns False.

The syntax for accessing the elements of a list is the same as the syntax for accessing the characters of a string. We use the index operator ( [] – not to be confused with an empty list). The expression inside the brackets specifies the index. Remember that the indices start at 0.

You can use Index to fetch a particular value based on the index from end. Use the caret notation, ^ to index from end. In the following example, you use Index to get the last element in the list. var myList = new List<int>{0, 1, 2}; var lastElement = myList[^1];

The includes() method returns true if an array contains a specified value. The includes() method returns false if the value is not found. The includes() method is case sensitive.

One approach to check if a string contains an element from a list is to convert the string and the list into sets and then check for the intersection between the sets. If the intersection is not an empty set, it means that the string contains an element from the list.

How to check if something contains something in C#? ›

Basic Syntax for Contains() Method

Contains(CheckString); The function returns true if CheckString is found within YourString , and false if it is not. As simple as that!

Type “=IF(COUNTIF” and press Tab. 4. Then you press enter. This function will return whether a value exists in a list in simple yes or no terms instead of exact number of time as shown section 1.1.

GetValue(Int32, Int32, Int32) method is used to get the value at the specified position in the three-dimensional Array. The indexes are specified as 32-bit integers. Syntax: public object GetValue (int index1, int index2, int index3);

How can I check if a key exists in a JavaScript object or array? You can use the in-operator or the hasOwnProperty() method to check if a key is in a JavaScript object or array. The in operator tells you if the key is there, and the hasOwnProperty() method shows if the key is a direct property of the object.

C# Linq Distinct() method removes the duplicate elements from a sequence (list) and returns the distinct elements from a single data source. It comes under the Set operators' category in LINQ query operators, and the method works the same way as the DISTINCT directive in Structured Query Language (SQL).

👉 Using HashSet :

HashSet is a data structure, that holds the unique items. Using HashSet , we can easily find the duplicates in array. This approach involves iterating over the input array and adding each element to a HashSet. If an element is already present in the HashSet, it is considered a duplicate.

To get the index of an item in a single line, use the FindIndex() and Contains() methods. int index = myList. FindIndex(a => a.