Unzip List of Tuples in Python

The task of unzipping a list of tuples in Python involves separating the elements of each tuple into individual lists, based on their positions. For example, given a list of tuples like [('a', 1), ('b', 4)], the goal is to generate two separate lists: ['a', 'b'] for the first elements and [1, 4] for the second elements.

Using zip()

The most efficient way to unzip a list of tuples is by using the built-in zip() function in combination with the unpacking operator *. This method allows us to "unzip" the list of tuples into separate lists in a single line.

x = [('a', 1), ('b', 4)]

# Using zip() with * to unzip the list
a, b = zip(*x)

# Convert the results to lists
a = list(a)
b = list(b)

print(a)
print(b)

['a', 'b']
[1, 4]

Explanation:* operator unpacks the list of tuples and the zip() function then pairs the corresponding elements into separate lists.

Using List Comprehension

List comprehension provides a more manual yet elegant way to unzip a list of tuples. By iterating through each tuple and extracting the first and second elements, we can create two new lists.

c = [('a', 1), ('b', 4)]

# Using list comprehension to unzip
a = [x[0] for x in c]
b = [x[1] for x in c]

print(a)
print(b)

['a', 'b']
[1, 4]

Explanation : list comprehension iterates through the list of tuples (c) and extracts the first and second elements of each tuple into separate lists.

Using For Loop

If we prefer a more explicit and manual approach, using a for loop to iterate through the tuples is a great alternative. This method is simple but might not be as concise or efficient as the previous methods.

c = [('a', 1), ('b', 4)]

# Using a for loop to unzip
a = []
b = []

for item in c:
    a.append(item[0])  # Add the first item of each tuple to list a
    b.append(item[1])  # Add the second item of each tuple to list b

print(a)
print(b)

['a', 'b']
[1, 4]

Explanation: In this method, we initialize two empty lists, a and b. Then, we loop through each tuple in the list c and append the first and second elements of the tuple to the respective lists .