LINQ method syntax in C Sharp (C#) - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is LINQ method syntax in C#?

LINQ method syntax uses chainable methods like Where(), Select(), and OrderBy() to query collections in a fluent style.

beginner

How does Where() method work in LINQ method syntax?

Where() filters a collection by a condition you provide as a function, returning only elements that satisfy that condition.

intermediate

Explain the difference between Select() and Where() in LINQ method syntax.

Where() filters elements based on a condition, while Select() transforms each element into a new form.

intermediate

What does this LINQ method syntax do? numbers.Where(n => n % 2 == 0).Select(n => n * 10)

It filters the numbers collection to keep only even numbers, then multiplies each of those even numbers by 10.

beginner

Can LINQ method syntax be chained? Give an example.

Yes, methods can be chained. Example: list.Where(x => x > 5).OrderBy(x => x).Select(x => x * 2) filters, sorts, then transforms the list.

Which LINQ method filters elements based on a condition?

A OrderBy()

B Select()

C Where()

D GroupBy()

Where() filters elements by a condition.

What does Select() do in LINQ method syntax?

A Transforms elements

B Filters elements

C Sorts elements

D Groups elements

Select() transforms each element into a new form.

How do you write a LINQ method syntax to get all numbers greater than 10 from a list named nums?

A nums.Select(n => n > 10)

B nums.GroupBy(n => n > 10)

C nums.OrderBy(n => n > 10)

D nums.Where(n => n > 10)

Where() filters elements; use nums.Where(n => n > 10).

Which of these is a valid LINQ method syntax chain?

A list.Where(x => x < 5).Select(x => x * 2)

B list.Select(x => x < 5).Where(x => x * 2)

C list.OrderBy(x => x * 2).Where(x => x < 5)

D list.GroupBy(x => x * 2).Select(x => x < 5)

You filter first with Where(), then transform with Select().

What type of argument do LINQ methods like Where() and Select() take?

A A string

B A lambda expression

C An integer

D A boolean

They take lambda expressions to define conditions or transformations.

Describe how you would use LINQ method syntax to filter and then transform a list of numbers.

Think about filtering first, then changing the values.

Explain the difference between LINQ query syntax and LINQ method syntax.

Focus on style and how queries are written.