Using LINQ Take to Select Specific Data

Using LINQ Take to Select Specific Data

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In this article, let's learn about how to use Take and TakeWhile in LINQ in .NET.

Note: If you have not done so already, I recommend you read the article on Using LINQ Single to Select Single Data in Collections.

Table of Contents

  1. Introduction
  2. Perform partition using Take
  3. Perform partition using Take with Range syntax
  4. Perform conditional partition using TakeWhile
  5. Summary

Introduction

We can perform partition and select specific piece of data from beginning of a collection using LINQ. We're going to use Take() and TakeWhile() methods. Let's take a look at each of these methods and how they work.

Perform partition using Take

When listing the items, its not always possible to list all the items. Sometimes we need to limit and partition the items from database or need a pagination in UI to display subset of records for better UX (User Experience) as not all the datas are required everytime unless its a reporting task. So Take(n) allows you to take only specific items from beginning of collection. It takes number of items given as input and returns n number of records from collection.

Code Sample - LINQ Take

Demo - LINQ Take Clause Demo

Let's try LINQ Take

  • We have Product class with following properties - Id, Name, Color, Price, Size
  • Enter the number of products you would like to list.
  • Click on Take by Range Products
  • Click on reset to try other combination
Id Name Color Price Size
1 HL Road Frame Black 1000 58
2 HL Road Frame Red 1000 58
3 HL Road Frame Black 1000 58
4 HL Road Frame Red 1000 58
5 HL Road Frame Brown 1000 58
6 HL Road Frame White 1000 58

Perform partition using Take with Range syntax

We can also use the Range Operator with Take() like Take(2..4), Take(..3), Take(^2..^4) or Take(3..).

Code Sample - LINQ Take using Range Operator

Demo - LINQ Take Clause with Range Demo

Let's try LINQ Take

  • We have Product class with following properties - Id, Name, Color, Price, Size
  • Enter the number of products you would like to list.
  • Click on Take Products
  • Click on reset to try other combination
Id Name Color Price Size
1 HL Road Frame Black 1000 58
2 HL Road Frame Red 1000 58
3 HL Road Frame Black 1000 58
4 HL Road Frame Red 1000 58
5 HL Road Frame Brown 1000 58
6 HL Road Frame White 1000 58

Perform conditional partition using TakeWhile

We can also extract data conditionally using TakeWhile while the condition evaluates to true. Note that Enumeration stops when the predicate function returns false for an element or when source contains no more elements.

Code Sample - LINQ TakeWhile

Demo - LINQ TakeWhile Clause Demo

Let's try LINQ TakeWhile

  • We have Product class with following properties - Id, Name, Color, Price, Size
  • Enter the condition based on which you like to select.
  • Click on TakeWhile Products
  • Click on reset to try other combination
Id Name Color Price Size
1 HL Road Frame Black 1000 58
2 HL Road Frame Red 1000 58
3 HL Road Frame Black 1000 58
4 HL Road Frame Red 1000 58
5 HL Road Frame Brown 1000 58
6 HL Road Frame White 1000 58

Summary

In this article we learn't how to locate partition and extract specific data within collection using Take and TakeWhile. We saw that there's an option to supply range of values using range operator. We also saw how we can pass an condition to partition data. All these can be used with any IEnumerable or IQueryable types.

  • Linq
  • Take
  • TakeWhile
  • Partition