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Chapter 1

Python Basics

An introduction to the basic concepts of Python. Learn how to use Python interactively and by using a script. Create your first variables and acquaint yourself with Python's basic data types.

slides_link
https://projector-video-pdf-converter.datacamp.com/735/chapter1.pdf

true

nb_of_exercises	title
3	Hello Python!

nb_of_exercises	title
5	Variables and Types

Hello Python!

type: VideoExercise
key: f644a48d5d
xp: 50

@projector_key d8fcd4c930027fa4e1c3870c7e7e0ff1

Your first Python code

type: NormalExercise
key: bdc52f0e19
lang: python
xp: 100
skills:
  - 2

It's time to run your first Python code!

Head to the code and hit the run code button to see the output.

@instructions

Hit the run code button to see the output of print(5 / 8).

@hint

Run the code first before submitting your answer so you have time to explore the output.

@pre_exercise_code

@sample_code

# Hit run code to see the output!
print(5 / 8)

@solution

# Hit run code to see the output!
print(5 / 8)

@sct

Ex().has_printout(0, not_printed_msg = "__JINJA__:Have you used `{{sol_call}}` to print out `5 / 8`?")
success_msg("Great! On to the next one!")

Python as a calculator

type: NormalExercise
key: 0f7c039428
lang: python
xp: 100
skills:
  - 2

Python is perfectly suited to do basic calculations. It can do addition, subtraction, multiplication and division.

The code in the script gives some examples.

Now it's your turn to practice!

@instructions

Print the sum of 4 + 5.
Print the result of subtracting 5 from 5.
Print the result of multiplying 3 by 5.
Print the result of dividing 10 by 2.

@hint

You'll need to use print() to generate an output.

@pre_exercise_code

@sample_code

# Addition


# Subtraction


# Multiplication


# Division

@solution

# Addition
print(4 + 5)

# Subtraction
print(5 - 5)

# Multiplication
print(3 * 5)

# Division
print(10 / 2)

@sct

Ex().has_printout(0, not_printed_msg = "Have you used `print(4 + 5)` to print out the result of your sum?")

Ex().has_printout(1, not_printed_msg = "Have you used `print(5 - 5)` to print out the result of your subtration?")

Ex().has_printout(2, not_printed_msg = "Have you used `print(3 * 5)` to print out the result of your multiplication?")

Ex().has_printout(3, not_printed_msg = "Have you used `print(10 / 2)` to print out the result of your division?")

success_msg("That's correct! Python can help you do the math, a characteristic that will be helpful for analysis as we grow our data skills.")

Variables and Types

type: VideoExercise
key: c2e396792e
xp: 50

@projector_key 433dcfcfedaee070cbf440491c402e3b

Variable Assignment

type: NormalExercise
key: 4bf65ad83e
lang: python
xp: 100
skills:
  - 2

In Python, a variable allows you to refer to a value with a name. To create a variable x with a value of 5, you use =, like this example:

x = 5

You can now use the name of this variable, x, instead of the actual value, 5.

Remember, = in Python means assignment, it doesn't test equality! Try it in the exercise by replacing ____ with your code.

@instructions

Create a variable savings with the value of 100.
Check out this variable by typing print(savings) in the script.

@hint

Type savings = 100 to create the variable savings.
After creating the variable savings, you can type print(savings).
Your final code should not include any ____.

@pre_exercise_code

@sample_code

# Create a variable savings
____

# Print out savings
____

@solution

# Create a variable savings
savings = 100

# Print out savings
print(savings)

@sct

Ex().check_object("savings").has_equal_value(incorrect_msg="Assign `100` to the variable `savings`.")
Ex().has_printout(0, not_printed_msg = "Print out `savings`, the variable you created, with `print(savings)`.")
success_msg("Great! Let's try to do some calculations with this variable now!")

Calculations with variables

type: NormalExercise
key: ff06cedeb4
lang: python
xp: 100
skills:
  - 2

You've now created a savings variable, so let's start saving!

Instead of calculating with the actual values, you can use variables instead.

How much money would you have saved four months from now, if you saved $10 each month?

@instructions

Create a variable monthly_savings, equal to 10 and num_months, equal to 4.
Multiply monthly_savings by num_months and assign it to new_savings.
Print the value of new_savings.

@hint

You can do calculations with variables the same way as with numbers so instead of 10 * 4, replace the numbers with the variables!
Use print() to see the amount in new_savings.
Take care to spell the variables correctly!

@pre_exercise_code

@sample_code

# Create the variables monthly_savings and num_months



# Multiply monthly_savings and num_months
new_savings = ____

# Print new_savings

@solution

# Create the variables monthly_savings and num_months
monthly_savings = 10
num_months = 4

# Multiply monthly_savings and num_months
new_savings = monthly_savings * num_months

# Print new_savings
print(new_savings)

@sct

Ex().check_object("monthly_savings").has_equal_value(incorrect_msg = "Did you save `10` to `monthly_savings` using `monthly_savings = 10`?")
Ex().check_object("num_months").has_equal_value(incorrect_msg = "Did you save `4` to `num_months` using `num_months = 4`?")
Ex().check_object("new_savings").has_equal_value(incorrect_msg = "Did you use the correct variables and symbols to multiply? Expected `monthly_savings * num_months` but got something else.")
# Ex().check_object("total_savings").has_equal_value(incorrect_msg = "Did you use the correct variables and symbols to add? Expected `savings + new_savings` but got something else.")

Ex().has_printout(0, not_printed_msg="Remember to print out `new_savings` at the end of your script.")

success_msg("You have $40 in new savings!")

Other variable types

type: NormalExercise
key: 006b48561f
lang: python
xp: 100
skills:
  - 2

In the previous exercise, you worked with the integer Python data type:

int, or integer: a number without a fractional part. savings, with the value 100, is an example of an integer.

Next to numerical data types, there are three other very common data types:

float, or floating point: a number that has both an integer and fractional part, separated by a point. 1.1, is an example of a float.
str, or string: a type to represent text. You can use single or double quotes to build a string.
bool, or boolean: a type to represent logical values. It can only be True or False (the capitalization is important!).

@instructions

Create a new float, half, with the value 0.5.
Create a new string, intro, with the value "Hello! How are you?".
Create a new boolean, is_good, with the value True.

@hint

To create a variable in Python, use =. Make sure to wrap your string in single or double quotes.
Only two boolean values exist in Python: True and False. TRUE, true, FALSE, false and other versions will not be accepted.

@pre_exercise_code

@sample_code

# Create a variable half


# Create a variable intro


# Create a variable is_good

@solution

# Create a variable half
half = 0.5

# Create a variable intro
intro = "Hello! How are you?"

# Create a variable is_good
is_good = True

@sct

Ex().check_object("half").has_equal_value(incorrect_msg = "Did you save the float, `0.5` to `half`?")

Ex().check_object("intro").has_equal_value(incorrect_msg = "Hmm, something is incorrect in your `intro` variable. Double check the spelling and make sure you've used quotation marks.")

Ex().check_object("is_good").has_equal_value(incorrect_msg = "Did you capitalize the boolean value? Remember you don't need to use quotation marks here.")

success_msg("Nice!")

Operations with other types

type: BulletExercise
key: 4d0d83cc02
xp: 100

Variables come in different types in Python. You can see the type of a variable by using type(). For example, to see type of a, execute: type(a).

Different types behave differently in Python. When you sum two strings, for example, you'll get different behavior than when you sum two integers or two booleans.

Time for you to test this out.

@pre_exercise_code

type: NormalExercise
key: f4e91c4ae9
xp: 50

@instructions

Add savings and new_savings and assign it to total_savings.
Use type() to print the resulting type of total_savings.

@hint

Assign savings + new_savings to a new variable, total_savings.
To print the type of a variable x, use print(type(x)).

@sample_code

savings = 100
new_savings = 40

# Calculate total_savings using savings and new_savings
____
print(total_savings)

# Print the type of total_savings
print(____)

@solution

savings = 100
new_savings = 40

# Calculate total_savings using savings and new_savings
total_savings = savings + new_savings
print(total_savings)

# Print the type of total_savings
print(type(total_savings))

@sct

# predefined
msg = "You don't have to change or remove the predefined variables."

Ex().multi(
    check_object('savings', missing_msg=msg).has_equal_value(incorrect_msg=msg),
    check_object('new_savings', missing_msg=msg).has_equal_value(incorrect_msg=msg)
)

Ex().multi(
    check_object("total_savings").has_equal_value(incorrect_msg="Add `savings` and `new_savings` to create the `total_savings` variable."),
    has_printout(0, not_printed_msg = "__JINJA__:Use `{{sol_call}}` to print out the type of `total_savings`.")
)

type: NormalExercise
key: f54fbf9bd9
xp: 50

@instructions

Calculate the sum of intro and intro and assign the result to doubleintro.
Print out doubleintro. Did you expect this?

@hint

Assign intro + intro to a new variable, doubleintro.
To print a variable x, write print(x) in the script.

@sample_code

intro = "Hello! How are you?"

# Assign sum of intro and intro to doubleintro
____

# Print out doubleintro
print(____)

@solution

intro = "Hello! How are you?"

# Assign sum of intro and intro to doubleintro
doubleintro = intro + intro

# Print out doubleintro
print(doubleintro)

@sct

# predefined
msg = "You don't have to change or remove the predefined variables."

Ex().check_object('intro', missing_msg=msg).has_equal_value(incorrect_msg=msg)

Ex().multi(
    check_object("doubleintro").has_equal_value(incorrect_msg  = "Have you stored the result of `intro + intro` in `doubleintro`?"),
    has_printout(0, not_printed_msg = "Don't forget to print out `doubleintro`.")
)

success_msg("Nice. Notice how `intro + intro` causes `\"Hello! How are you?\"` and `\"Hello! How are you?\"` to be pasted together.")

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chapter1.md

chapter1.md

Hello Python!

Your first Python code

Python as a calculator

Variables and Types

Variable Assignment

Calculations with variables

Other variable types

Operations with other types

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Hello Python!

Your first Python code

Python as a calculator

Variables and Types

Variable Assignment

Calculations with variables

Other variable types

Operations with other types