Problem Formulation and Solution Overview
βΉοΈ Info: A Python set is a collection of unique item(s) saved in no particular order (unordered). A set
cannot be changed. However, elements can be added and removed. Sets can also perform calculations like union, intersection, and much more!
To make it more interesting, we use the following practical scenario in this tutorial:
Method 1: Use add()
This method uses the add()
function to add a single element to an empty set.
dog_names = set() dog_names.add('Chewie') print(dog_names)
The first line in the above code declares an empty set. This saves to dog_names
.
The following line uses the add()
function and passes it one (1) argument. In this case, a string ('Chewie'
). This action adds the element to the dog_names
set.
On the next line, the contents of dog_names
is output to the terminal.
{'Chewie'} |
No error is displayed if we attempt to add the same element again. However, the second occurrence is ignored.
dog_names = set() dog_names.add('Chewie') dog_names.add('Chewie') print(dog_names)
As expected, the contents of dog_names
remain the same.
{'Chewie'} |
Method 2: Use update() with list
This method uses the update()
function in conjunction with list to add a list of items to a set.
sold_yesterday = ['Griffin', 'Tinsley', 'Watson'] dog_names.update(sold_yesterday) print(dog_names)
This example builds on the existing dog_names
set from Method 1.
In this regard, a list of all dogs sold yesterday at PetBoutique has been created. The results save to sold_yesterday
in a list format.
The following line uses the update()
function and passes it one (1) argument, the list, sold_yesterday
and converts this list to a set.
On the next line, the contents of dog_names
are output to the terminal.
{'Griffin', 'Watson', 'Tinsley', 'Chewie'} |
As expected, the dog_names set now contains four (4) dog names in no particular order.
Method 3: Use the Pipe Operator
This method uses the Pipe Operator (|
) to add a new set to an existing set.
sold_today = set() sold_today.add('Scout') all_sales = dog_names | sold_today print(all_sales)
This example builds on the existing dog_names
set from Method 1 and Method 2.
In this regard, a list of all dogs sold today at PetBoutique ππβπ¦Ίπ© is created. The results save to sold_today
.
On the following line, a new dog name is added to the sold_today
set.
Next, the two (2) sets are joined using the pipe (|
) operator. The results save to all_sales
.
On the following line, the contents of all_sales
are output to the terminal.
{'Scout', 'Chewie', 'Griffin', 'Tinsley', 'Watson'} |
As expected, the dog_names set now contains five (5) dog names in no particular order.
Method 4: Use union
This method uses the union()
method to add a new set to an existing set.
last_week_sales = {'Scout', 'Chewie', 'Griffin', 'Tinsley', 'Watson'} this_week_sales = ['Axel', 'Pixie', 'Gunner'] all_sales = last_week_sales.union(this_week_sales) print(all_sales)
The first line in the above code snippet declares a new set (different from Method 1). The results save to last_week_sales
.
The following line declares a list containing dog sales this week. The results save to this_week_sales
.
The next line merges the two (2) sets using the union
function. The results save to all_sales
.
On the following line, the contents of all_sales
are output to the terminal.
{'Griffin', 'Watson', 'Tinsley', 'Scout', 'Chewie', 'Pixie', 'Axel', 'Gunner'} |
As expected, the dog_names
set now contains eight (8) dog names in no particular order.
Summary
This article has provided four (4) ways to add elements to a set to select the best fit for your coding requirements.
Good Luck & Happy Coding!
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