Basic Data Structures

Question 1

What is a data type?

Answer 1

A category for values and every value belongs to exactly one data type.

Question 2

How can you check the type of a variable or value?

Answer 2

Use the function type()

Question 3

What is an integer?

Answer 3

A value that is a whole number

Question 4

What is the operator for exponent?

Answer 4

**

Question 5

What is the operator for modulus?

Answer 5

%

Question 6

What is the operator for integer division?

Answer 6

//

Question 7

What are the operators for addition, subtraction, multiplication and division?

Answer 7

+ - * /

Question 8

How is data typing in Python?

Answer 8

Dynamic - variables can change types

Question 9

What is None in Python?

Answer 9

The null value, a data type of the class NoneType
different from empty string, zero or False

Question 10

What is a use case for the modulus (%)?

Answer 10

Perform an action every nth time

E.g. every third session the system will require the user to login

for i in session_number:
if i % 3 == 0:
#require login

Question 11

What is the order of operations in Python?

Answer 11

1. exponentiation and root extraction
2. multiplication and division
3. addition and subtraction

Question 12

How can you change the order of operations?

Answer 12

Use parentheses

Question 13

How can you add a value to an existing variable?

Answer 13

Use the += operator

e.g. num = 5
num += 2

Question 14

What happens when you try to divide by 0?

Answer 14

You get a ZeroDivisionError

Question 15

What is a floating point?

Answer 15

A value with a decimal point

Question 16

What type of data do you get when you divide 2 integers?

Answer 16

a float

Question 17

What type of data do you get when you divide 2 integers using the // operator?

Answer 17

an integer

Question 18

What is a string?

Answer 18

A series or list of characters.
Each character has an index, starting at 0.

Anything inside single (‘’) or double (“”) quotes

Question 19

If name = “Marianne”, name[4] = ?

Answer 19

a

Question 20

How do you concatenate two strings?

Answer 20

Use the “+” operator

Question 21

How can you concatenate a number to some text?

Answer 21

Explicitly convert the integer to a string

e.g. “John is “ + str(6) + “ feet tall.”

Question 22

Print “JohnJohnJohnJohn” without typing John more than once

Answer 22

print(“John” * 4)

Question 23

How can you create multi-line strings?

Answer 23

Use three single (‘’’) or double (“””) quotes

Question 24

How do you write ‘It’s a lovely day!’ without getting an error?

Answer 24

“It’s a lovely day!” or ‘It's a lovely day!’

Question 25

How do you add a new line and a tab to a string?

Answer 25

\n for new line | \t for tab

Question 26

What is a string method?

Answer 26

An action that Python can perform on a string

Question 27

Change the value of variable "name" so that each word begins with a capital letter

Answer 27

name.title()

Question 28

Change the value of variable "name" so that all letters are lowercase

Answer 28

name.lower()

Question 29

Change the value of variable "name" so that every letter is uppercase

Answer 29

name.upper()

Question 30

What are f-strings?

Answer 30

f-strings are string literals that have an f at the beginning and curly braces containing expressions that will be replaced with their values. (source: Real Python)

Question 31

With name = "John", use f-strings to print "Happy birthday, John"

Answer 31

f"Happy birthday, {name}!"

Question 32

What are whitespaces?

Answer 32

nonprinting characters (space, tab, end-of-line symbol)

Question 33

How do you strip whitespaces from the right end of a string, from the left end and from both ends?

Answer 33

var_name.rstrip() var_name.lstrip() var_name.strip()

Question 34

What are booleans?

Answer 34

True or False values

Question 35

What Python objects are mutable?

Answer 35

list, set, dict

Question 36

What Python objects are immutable?

Answer 36

bool, int, float, tuple, str, frozenset

Question 37

What is the difference between mutable and immutable objects?

Answer 37

Mutable objects can be changed after they are created, while immutable objects can't

Question 38

Capitalize the first letter of 'string', with all other characters lowercased

Answer 38

``` string.capitalize() # doesn't modify the original string ```

Question 39

Get "---John---" from variable name = "John"

Answer 39

name.center(10, '-') ``` # 10 is the total length of the string after padding # if no second argument, default padding is blank space ```

Question 40

What is .casefold() and should I use it?

Answer 40

.casefold() is a more aggressive version of .lower() and should be used when dealing with Unicode text or user input.

Question 41

Get the number of times the substring "and" is present in the variable string_var = 'John and Mary and Simon and Jane', then assign it to substring_count

Answer 41

substring_count = string_var.count('and')

Question 42

Return True if variable 'proposition' is a question.

Answer 42

proposition.endswith('?')

Question 43

Return the index of first occurrence of substring 'and' in string variable 'names'. If not found, return -1

Answer 43

names.find('and')

Question 44

Return True if all the letters in string variable 'name' are in lowercase, else return False

Answer 44

name.islower()

Question 45

Return True if all characters in string variable 'name' are in uppercase, else return False

Answer 45

name.isupper()

Question 46

Take variable names = "John, Mary, Rebecca, Oliver" and make a list of these names, called names_list.

Answer 46

names_list = names.split(",")

Question 47

Turn the value "John and Rebecca" of variable names into "John or Rebecca" without using the assignment operator ('=')

Answer 47

names.replace('and', 'or')