C# LINQ Masterclass: Data Manipulation with 30+ Exercises

Mastering linq in C# helps you filter a customer list by city, age, and active status using conditional predicates, including an optional active-only filter and test validations.

Use the OfType operator to filter elements by type from a non-generic collection such as an array list. Learn how to extract integers, strings, and DateTime values, with tests passing.

Explore how to filter a mixed log collection by type using OfType in Linq, extracting error, warning, and info logs.

Master the select operator to transform collections into simple data, such as extracting emails from a list of employee objects. Build a static helper and tests to verify email extraction.

Flatten nested task collections across projects using select many to produce a single list of all tasks for a project management tool.

Mastering LINQ in C# demonstrates using select and select many to extract names and hobbies from people, filtering by age to show hobbies of those older than 30.

Learn to sort a list of employees by age using the order by method in LINQ, including ascending and descending options, with practical debugging and console visualization.

Learn to sort employees by department (ascending) and then by name using order by and then by in LINQ, demonstrating multi-level sorting and returning sorted lists.

Group employees by department using the group by operator, implement a method that clusters a list of employees into finance, HR, and IT groups, and print each group for visualization.

Discover how to create and use a lookup with category keys in LINQ, compare it to group by, and see when to apply one-to-many lookups for quick data access.

Apply linq join to connect authors and their books in a one-to-many scenario, producing a list of strings with each book title attributed to its author.

Master the group join in LINQ by grouping books under their authors in a one-to-many relationship, compare it with join, and produce strings listing each author's books.

Leads you through cleaning duplicate addresses with the distinct operator by overriding equality and GetHashCode in an address class, ensuring accurate, unique results for a marketing list.

Combine sports and arts activities into a master list using the linq union operator, implementing equality by name to remove duplicates. Visualize results and explore default ordering of unique activities.

Demonstrate the LINQ intersect operator to find common books between two favorite-book lists, implementing equals and gethashcode in the book class and printing the results.

Learn how the linq except operator subtracts an opt-out list from a signed-up list to yield a unique final participants list via a practical coding exercise.

Analyze a bookstore inventory to count books by genre using the count operator. Review a book class with title and genre and learn to print and count specified genres.

Learn to use the sum operator in LINQ to compute total revenue from beverage sales and by category, filtering with where and multiplying price by quantity in coffee shop scenario.

Apply the min operator to filter runners by age category and extract the fastest finish time, using a race results analyzer and unit tests to validate results.

Learn to apply the max operator to find the highest sale by senior employees, filtering by more than five years of experience and the sale year within a sales analyzer.

Filter grades by subject and compute the average using the average operator, focusing on mathematics. Implement the subject average calculation in the SubjectGradeCalculator and return zero when no data.

Use the any operator in LINQ to determine if any user in a library system has overdue books by comparing each borrowed book's due date to the current date.

Learn how to use the all operator in linq to verify every student meets both coursework and final exam passing scores, with contrasts to any and practical console examples.

Explore how to use the contains operator in LINQ to check product availability by projecting product ids and verifying their presence in the inventory list, with practical console tests.

Use the first operator to find the first person in a list who matches criteria, such as age greater than or equal to 30, and return it.

Explore the first or default operator in LINQ by locating the first available book in a specified genre, ensuring availability and handling cases with no matching results.

Explore the last or default operator in LINQ to find the last order matching criteria by sorting by order date descending, using filter operators, and validating results with unit tests.

Demonstrates using linq's single operator to find a student by id in a list, throwing exceptions when no match or multiple matches exist and highlighting the single versus general approaches.

Explore how SingleOrDefault and Single work in LINQ through a banking scenario that checks for a unique account number, returning null on not found or duplicates, with exception behavior illustrated.

Demonstrates using the default if empty operator in LINQ to provide a default value for an empty student collection and to calculate the average age.

Filter negative transactions using where, sum their amounts, and return a default value when none exist with DefaultIfEmpty in a financial transaction processor.