Variables and Types
Variables are a very basic concept in programming. They are places where you can store data and access them later. This tutorial will go over a few basic types of variables.
Numbers
Python supports two types of numbers - integers(whole numbers) and floating point numbers(decimals). (It also supports complex numbers, which will not be explained in this tutorial).
To define an integer, use the following syntax:
myint = 7
print(myint)
To define a floating point number, you may use one of the following notations:
myfloat = 7.0
print(myfloat)
myfloat = float(7)
print(myfloat)
Strings
Strings are defined either with a single quote or a double quotes.
mystring = 'hello'
print(mystring)
mystring = "hello"
print(mystring)
The difference between the two is that using double quotes makes it easy to include apostrophes (whereas these would terminate the string if using single quotes)
mystring = "Don't worry about apostrophes"
print(mystring)
Simple operators can be executed on numbers and strings:
one = 1
two = 2
three = one + two
print(three)
hello = "hello"
world = "world"
helloworld = hello + " " + world
print(helloworld)
Mixing operators between numbers and strings is not supported:
# This will not work!
one = 1
two = 2
hello = "hello"
print(one + two + hello)
Exercise
The target of this exercise is to create a string, an integer, and a floating point number. The string should be named mystring and should contain the word "hello". The floating point number should be named myfloat and should contain the number 10.0, and the integer should be named myint and should contain the number 20.
# change this code
mystring = None
myfloat = None
myint = None
# testing code
print("String: %s" % mystring)
print("Float: %f" % myfloat)
print("Integer: %d" % myint)
# change this code
mystring = "hello"
myfloat = 10.0
myint = 20
# testing code
if mystring == "hello":
print("String: %s" % mystring)
if isinstance(myfloat, float) and myfloat == 10.0:
print("Float: %f" % myfloat)
if isinstance(myint, int) and myint == 20:
print("Integer: %d" % myint)
test_object('mystring', incorrect_msg="Don't forget to change `mystring` to the correct value from the exercise description.")
test_object('myfloat', incorrect_msg="Don't forget to change `myfloat` to the correct value from the exercise description.")
test_object('myint', incorrect_msg="Don't forget to change `myint` to the correct value from the exercise description.")
test_output_contains("String: hello",no_output_msg= "Make sure your string matches exactly to the exercise desciption.")
test_output_contains("Float: 10.000000",no_output_msg= "Make sure your float matches exactly to the exercise desciption.")
test_output_contains("Integer: 20",no_output_msg= "Make sure your integer matches exactly to the exercise desciption.")
success_msg("Great job!")