Common string methods in C Sharp (C#) - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the ToUpper() method do in C# strings?

It converts all characters in the string to uppercase letters.

beginner

How does the Contains() method work on a string?

It checks if a specified substring exists inside the string and returns true or false.

beginner

What is the purpose of the Trim() method?

It removes all leading and trailing white spaces from the string.

beginner

Explain what Replace(oldValue, newValue) does in a string.

It replaces all occurrences of oldValue in the string with newValue.

intermediate

What does the Substring(startIndex, length) method return?

It returns a new string that starts at startIndex and has the specified length.

Which method would you use to check if a string starts with a specific word?

A StartsWith()

B EndsWith()

C Contains()

D IndexOf()

The StartsWith() method checks if the string begins with the specified substring.

What does "Hello World".IndexOf("World") return?

A 0

B 6

C -1

D 11

It returns the starting index of the substring "World" which is 6.

Which method removes spaces only from the start and end of a string?

A Remove()

B Replace()

C Trim()

D Split()

Trim() removes whitespace from both the beginning and end of a string.

If you want to change all 'a' characters to 'o' in a string, which method do you use?

A Replace('a', 'o')

B Remove('a')

C Insert('o')

D Substring('a', 'o')

Replace() changes all specified characters to new ones.

What will "Example".ToLower() return?

A "ExAmPlE"

B "EXAMPLE"

C "Example"

D "example"

ToLower() converts all letters to lowercase.

Describe how you would check if a string contains a certain word and then replace it with another word.

Think about first finding the word, then changing it.

Explain the difference between Substring() and Remove() methods in strings.

One keeps a piece, the other cuts out a piece.