Python: Map dictionary

Last update on March 27 2025 12:56:53 (UTC/GMT +8 hours)

70. Map List Values to Dictionary Using a Function

Write a Python program to map the values of a given list to a dictionary using a function, where the key-value pairs consist of the original value as the key and the result of the function as the value.

• Use map() to apply fn to each value of the list.
• Use zip() to pair original values to the values produced by fn.
• Use dict() to return an appropriate dictionary.

Sample Solution:

Python Code:

# Define a function 'test' that takes two arguments: 'itr' (an iterable) and 'fn' (a function).
def test(itr, fn):
    # Use the 'zip' function to pair each element from 'itr' with the result of applying 'fn' to that element.
    # Convert the zipped pairs into a dictionary where the elements from 'itr' are keys, and the results of 'fn' are values.
    return dict(zip(itr, map(fn, itr)))

# Call the 'test' function with an iterable [1, 2, 3, 4] and a lambda function that squares its input.
# The lambda function calculates the square of each element in the iterable.
result = test([1, 2, 3, 4], lambda x: x * x)

# Print the resulting dictionary.
print(result)

Sample Output:

{1: 1, 2: 4, 3: 9, 4: 16}

Flowchart:

For more Practice: Solve these Related Problems:

• Write a Python program to convert a list of numbers into a dictionary where each key is the number and its value is the square of the number.
• Write a Python program to map a list of strings to a dictionary where each key is the string and the value is its length.
• Write a Python program to implement a function that takes a list and a function, returning a dictionary mapping each element to the function’s result.
• Write a Python program to use dictionary comprehension to map each element of a list to its factorial value.

Python Code Editor:

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