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# Python Set and Booleans

Updated: Sep 1, 2020

## 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()

```
```

```
```
#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:

```

```
```
#Show
x
```

Output:

```
{1, 2}

```

Example:

```
# Try to add the same element
```
```
#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.