String length and membership test in Python - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the len() function do when used with a string?

The len() function returns the number of characters in the string, including spaces and special characters.

beginner

How can you check if a character or substring exists inside a string in Python?

You can use the in keyword to test membership. For example, 'a' in 'apple' returns True.

beginner

What will len('Hello World') return?

It will return 11 because there are 11 characters including the space.

beginner

What is the result of 'x' in 'example'?

It returns True because the character 'x' is present in the string 'example'.

beginner

Can in be used to check for substrings longer than one character?

Yes, in works for any substring. For example, 'cat' in 'concatenate' returns True.

What does len('Python') return?

A 6

B 5

C 7

D 0

len() counts all characters. 'Python' has 6 letters.

Which expression checks if 'a' is in the string 'data'?

A 'data' in 'a'

B 'a' not in 'data'

C 'a' in 'data'

D 'data' == 'a'

The in keyword checks membership. 'a' in 'data' is True.

What will 'z' in 'pizza' return?

A False

B True

C Error

D None

'z' is present in 'pizza', so the result is True.

What is the length of the string '' (empty string)?

A None

B 1

C Error

D 0

An empty string has zero characters, so length is 0.

Which of these is True?

A 'cat' in 'concatenate'

B 'dog' in 'concatenate'

C 'bat' in 'concatenate'

D 'rat' in 'concatenate'

'cat' is a substring of 'concatenate', so it returns True.

Explain how to find the number of characters in a string and how to check if a character is inside that string.

Think about counting characters and searching inside text.

Describe what happens when you use in with a substring longer than one character.

Consider if 'cat' is in 'concatenate'.