Python Basics Recap

Overview

Teaching: 0 min
Exercises: 0 min

Questions

• Python Refresher

Objectives

• Understanding key concepts in Python

This course follows on from the python introduction course. To ensure that we are starting from similar positions, there follows a short multiple choice quiz on key python concepts that we will be building on through this course.

Variables and Lists

1. Assigning a value to a variable

We wish to store the string Cat as a value in the variable animal, which of these lines of code will do this for us?

1. animal = 'Cat'
2. animal = Cat
3. Cat = animal
4. animal(Cat)

Solution

Answer 1 is correct

2. Assigning values to a list

We wish to create a list of values, which of these lines of code is valid to do this?

1. varlist = [34, 57, '2d']
2. varlist = (12, 'vr', 95)
3. varlist = 'xcf', 12, 97

Solution

Answer 1 is correct

3a. Indexing characters in a string

Lists and strings both contain multiple indexed values (in the case of strings these are specifically individual characters rather than other values). If we have a variable animal which contains the string penguin, which of these options will print the first character (p) for us?

1. print(animal[0])
2. print(animal[1])
3. print(animal['p'])

Solution

Answer 1 is correct

3b. Indexing characters in a string (slicing)

We can also select whole sections of lists and strings, not just single elements. Using the same variable animal, containing the string penguin, as above, which of these options will print the last 2 characters for us? (Note that there is more an one correct answer)

1. print(animal[5:])
2. print(animal[6:])
3. print(animal[6:7])
4. print(animal[5:7])
5. print(animal[-2:])
6. print(animal[:-2])

Solution

Answers 1, 4, and 5 are correct

Loops

4. Constructing a for loop

Please write a simple for loop which will print out each of the characters in the animal variable one at a time.

Solution

for char in animal:
    print(char)

Software Modules

5. Loading new functions

We want to use the functions in the numpy library in our code. How do we open this library in our code?

1. import numpy
2. load numpy
3. open numpy

Solution

Answer 1 is correct

If statements and conditionals

6. Conditionals

Which of these conditional tests returns a True result?

1. 4 > 3
2. 'a' != 'b'
3. 6 >= 6.0
4. '3' == 3
5. 3 > 'c'

Solution

Answers 1, 2, and 3 return True results. 4 returns False. 5 raises an Error.

7. If statements

What is printed when this if statement is used?

if 4 > 5:
    print('A')
elif 4 <= 5:
    print('B')
elif 4 < 5:
    print('C')
else:
    print('D')

1. A
2. B
3. C
4. B and C
5. D
6. A and D

Solution

B. Both 4 <= 5 and 4 < 5 would return a True result, but the if statement is exited as soon as the True result is returned.

Key Points

• variables

• lists

• indexing

• loops

• conditionals