Python Set and Booleans

Python Set and Booleans

There are two other object types in Python that we should cover: Sets and Booleans.

Sets

Sets are an unordered collection of unique elements. We can construct them by using the set() function. Let's go ahead and make a set to see how it works.

Example:

x = set()

# We add to sets with the add() method
x.add(1)

#Show
x

Output:

1

Note the curly brackets. This does not indicate a dictionary! Although you can draw analogies as a set is a dictionary with only keys.

We know that a set has only unique entries. So what happens when we try to add something that is already in a set?

Example:

# Add a different element 
x.add(2)

 #Show
 x
 

Output:

{1, 2}

Example:

 # Try to add the same element
 x.add(1)
 

#Show 
x

Output:

{1, 2}

Notice how it won't place another 1 there. That's because a set is only concerned with unique elements! We can cast a list with multiple repeat elements to a set to get the unique elements. For example:

Example:

# Create a list with repeats 
list1 = [1,1,2,2,3,4,5,6,1,1]

# Cast as set to get unique values 
set(list1)

Output:

  {1, 2, 3, 4, 5, 6}

Booleans

Python comes with Booleans (with predefined True and False displays that are basically just the integers 1 and 0). It also has a placeholder object called None. Let's walk through a few quick examples of Booleans.

They are of type bool -

Example:

# Set object to be a boolean
a=True

# Show 
a

Output:

True

We can also use comparison operators to create booleans.

Example:

 # Output is boolean
 1 > 2
 

Output:

False

We can use None as a placeholder for an object that we don't want to reassign yet:

Example:

 # None placeholder
 b = None
 

# Show
print(b)

Output:

None 

That's it! You should now have a basic understanding of Python objects and data structure types.

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