How to Take User Input for Tuples and Sets?

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Problem Statement

  • Create a tuple from user input in Python.
  • Create a set from user input in Python.

How to take Set as an Input from the User?

Method 1: Using a Set Comprehension

Approach: The simplest way to take a set as an input from the user is to use a set comprehension.

Set Comprehension is quite similar to a list comprehension. It is a concise way to create a set in Python with the help of curly braces.
Syntax:
{expression for element in context}
Example: {a for a in range(5)} will create a set = {0, 1, 2, 3, 4}

To learn more about set comprehensions refer to this article: “A Simple Introduction to Set Comprehension in Python“

Solution:

x = input('some text : ')
x = {a for a in x.split(",")}
print(x)

Output:

some text : apple, mango, orange
{' orange', 'apple', ' mango'}

Method 2: Using set.add()

In the previous approach, we had to enter the entire set all at once. But now we will have a look at another method using which we can ask the user to enter the values one by one. The user can feed in values as long as he wants and type exit once he wants to stop feeding in more values. The values can be appended to a tuple one by one using the add() method.

Solution: Please follow the comments mentioned in the script to understand how it works.

# Prompt user to enter a value
set_val = input('Enter a value (enter exit to stop!): ')
# initialize the resultant set
set_x = {}
# if value entered by user is not exit then store the value in set_x
if set_val != 'exit':
    set_x = set(set_val)
# Iterate as long as user keeps entering values
while True:
    # evaluate if block if value entered by user is not exit
    if set_val != 'exit':
        # prompt the user to enter next value
        set_val = input('Enter a value (enter exit to stop!): ')
        # evaluate if block if value entered by user is not exit
        if set_val != 'exit':
            # append/add value entered by user to set_val 
            set_x.add(set_val)
    # if value entered by user is exit then break out of the loop
    else:
        break
# print the resultant set
print(set_x)

Output:

Enter a value (enter exit to stop!): 1
Enter a value (enter exit to stop!): 2
Enter a value (enter exit to stop!): 3
Enter a value (enter exit to stop!): finxter
Enter a value (enter exit to stop!): exit
{'2', '1', 'finxter', '3'}

How to take Tuple as an Input from the User?

Method 1: Typecasting a List Comprehension to a Tuple

In Python, comprehensions can be performed upon dictionaries, lists and sets but tuple comprehensions do not produce feasible outputs. The result of applying comprehension to a tuple is a generator object. Thus, the work-around to this problem is to use a list comprehension to solve our problem and then typecast the output to a tuple.

Thus, we will use a list comprehension to accept values from the user and then typecast it to a tuple.

Solution:

x = input('Enter the tuple : ')
x = tuple(int(a) for a in x.split(","))
print(x)

Output:

Enter some text : 1,2,3,4,5
('1', '2', '3', '4', '5')

Method 2: By Appending Value to a Tuple

If you want the user to enter values one by one and store them in a tuple then the following method will help you to do that. You can prompt the user to enter a value. As long as the user wants to enter a value, the program allows him/her to do so with the help of a loop. You can keep storing the values one by one in a tuple and finally display the contents of this tuple as an output.

Solution:

# Prompt user to enter a value
tup_val = input('Enter a value (enter exit to stop!): ')
# initialize the resultant tuple
tup_x = ()
# if value entered by user is not exit then store the value in tup_x
if tup_val != 'exit':
    tup_x = tuple(tup_val)
# Iterate as long as user keeps entering values
while True:
    # evaluate if block if value entered by user is not exit
    if tup_val != 'exit':
        # prompt the user to enter next value
        tup_val = input('Enter a value (enter exit to stop!): ')
        # evaluate if block if value entered by user is not exit
        if tup_val != 'exit':
            # append/add value entered by user to tup_val
            tup_x = tup_x + (tup_val,)
   # if value entered by user is exit then break out of the loop
    else:
        break
# print the resultant set
print(tup_x)

Output:

Enter a value (enter exit to stop!): 1
Enter a value (enter exit to stop!): 3
Enter a value (enter exit to stop!): 5
Enter a value (enter exit to stop!): Mercury
Enter a value (enter exit to stop!): Venus
Enter a value (enter exit to stop!): Earth
Enter a value (enter exit to stop!): exit
('1', '3', '5', 'Mercury', 'Venus', 'Earth')

Related Questions

How to Add Item to a Tuple in Python?

To add an item to a tuple you can simply use the + operator as shown in the following example.

Example:

tup = ('Python', 'Java')
tup = tup + ('C++',)
print(tup)

# ('Python', 'Java', 'C++')

How to Append Values to a Set in Python?

You can append values to a set using the add() function. The add() function effectively appends single values to a set. To append multiple values from another list, tuple, frozen set to the set, you can use the update method.

Example:

# append single value
my_set = {'Brock', 'Rock'}
my_set.add('John')
print(my_set)

# append multiple values
my_set = {'One', 'Two', 'Three'}
my_set.update(['Four', 'Five'])
print(my_set)

# append an entire tuple as a single item
my_set = {1, 2, 3}
my_set.add(('One', 'Two', 'Three'))
print(my_set)

Output:

('Python', 'Java', 'C++')
{'Brock', 'John', 'Rock'}
{'Two', 'Four', 'One', 'Five', 'Three'}
{('One', 'Two', 'Three'), 1, 2, 3}

Conclusion

Phew! That was it for this article. We unearthed the answers to some of the frequently asked questions here –

I hope this article has helped you in your coding journey. Please stay tuned and subscribe to keep getting soutions and enhance your Python skills. Happy learning!

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