In this lesson we will learn how to work with various datatypes.

String workflows

There are a number of things you can do with strings.

You can capitalize the first letter of a string using .capitalize(), like this:

print("hello".capitalize()) # Output: Hello

You can capitalize every letter in a string using .upper(), like this:

print("hello".upper()) # Output: HELLO

You can make every letter in a string lower-case using .lower(), like this:

print("HELLO".lower()) # Output: hello

You can also use these on a variable containing a string:

myString = "hello"
print(myString.capitalize()) # Output: Hello

This allows you to output strings in multiple ways:

myString = "HeLlO"
print(myString.upper()) # Output: HELLO
print(myString.lower()) # Output: hello

Integer workflows

There are several things you can do with integers, mainly math.

You can add two integers together using +:

print(5 + 5) # Output: 10

You can subtract two integers using -:

print(10 - 5) # Output: 5

You can multiply two integers using *:

print(5 * 5) # Output: 25

You can divide two integers using /:

print(25 / 5) # Output: 5.0

You’ll notice that dividing turns the integer into a float, I’ll explain more about that later.

You can use this symbols (operators) on variables too:

a = 5
b = 10
print(a + b) # Output: 15

You can also use them directly on a variable:

a = 5
a += 10 # Adds the existing value (5) to the new value (10)
print(a) # Output: 15

These operators also work on floats:

print(3.2 + 4.6) # Output: 7.8
print(8.2 - 5.3) # Output: 2.8999999999999995
print(1.4 * 3.2) # Output: 4.4799999999999995
print(2.2 / 1.2) # Output: 1.8333333333333335

However, you will notice that the numbers are… messy. I’ll explain why that happens and how to avoid it in a future lesson.

The + operator can also be used on strings, but instead of adding the values arithmetically, it will join them together. For example:

print("Hello " + "World") # Output: Hello World

You can’t directly join an integer with a string, but there is a workaround which we will now cover.

Converting datatypes

We’ve talked about a few different datatypes, now let’s talk about how to convert between them.

Strings can store any text. That can be letters, numbers, special characters, etc. Integers can only store non-decimal numbers, and floats expand to include decimals. So how can you use them interchangeably?

Each datatypes has a function for this. str() for strings, int() for integers, and float() for floats. To convert them, you use them like this:

myInteger = 5
myString = str(myInteger)
print(myString) # Output: 5 (but it's a string instead of an integer)

Like with the print statement, it’s important to keep the right syntax.

This allows you to do math with numbers that happen to be stored as strings. For example:

a = 5
b = "10"
c = a + int(b) # Converts the string "10" to a plain integer
print(c) # Output: 15

Note that something like this:

a = "hello"
b = int(a)
print(b)

Will not work, because “hello” cannot be an integer.

With this knowledge, let’s go back to dividing integers. As you’ll remember, when you divide two integers, the output is automatically a float. This is so if you divide something like 5 / 2, it will be able to output 2.5. However, if the output is always going to be a non-decimal number, then you can convert the output back to an int like this:

print(int(25 / 5)) # Output: 5

Finally, you can also use convertion to join a string and an integer together:

print("My favorite number is: " + str(5)) # Output: My favorite number is: 5