Python – Get first element from a List of tuples

Last Updated : 21 Dec, 2023

In this article, we will discuss how to get the first element in the list of tuples in Python.

Tuples are an immutable data structure in Python, meaning we can not update its state after creation. Lists are similar to tuples but they are mutable data structures.

Create a list of Tuples

Python3

# create tuples with college
# id and name and store in a list
data = [(1, 'sravan'), (2, 'ojaswi'),
        (3, 'bobby'), (4, 'rohith'),
        (5, 'gnanesh')]
 
# display data
print(data)

Output

[(1, 'sravan'), (2, 'ojaswi'), (3, 'bobby'), (4, 'rohith'), (5, 'gnanesh')]

How to Access First Element from a List of Tuples

There are different methods to access the first element from a list of Tuples in Python. We have discussed them below with examples for better understanding.

Method 1: Using iteration (for loop)

We can iterate through the entire list of tuples and get first by using the index, index-0 will give the first element in each tuple in a list.

Syntax:

for var in list_of_tuple:
print(var[0])

Example: Here we will get the first IE student id from the list of tuples.

Python3

# create tuples with college id
# and name and store in a list
data = [(1, 'sravan'), (2, 'ojaswi'),
        (3, 'bobby'), (4, 'rohith'),
        (5, 'gnanesh')]
 
# iterate using for loop
# to access first elements
for i in data:
    print(i[0])

Output

Method 2: Using zip function

Zip is used to combine two or more data/data structures. Here we can use the zip() function by using the index as 0 to get the first element.

Syntax: list(zip(*data))[0]

Python3

# create tuples with college id
# and name and store in a list
data = [(1, 'sravan'), (2, 'ojaswi'),
        (3, 'bobby'), (4, 'rohith'),
        (5, 'gnanesh')]
 
# get first element using zip
print(list(zip(*data))[0])

Output

(1, 2, 3, 4, 5)

Method 3: Using map() with itemgetter() method

Here we are using the map function along with the itemgetter() method to get the first elements, here also we are using index – 0 to get the first elements. itemgetter() method is available in the operator module, so we need to import the operator

Syntax: map(operator.itemgetter(0), data)

Python3

import operator
 
# create tuples with college id
# and name and store in a list
data = [(1, 'sravan'), (2, 'ojaswi'),
        (3, 'bobby'), (4, 'rohith'),
        (5, 'gnanesh')]
 
# map the data using item
# getter method with first elements
first_data = map(operator.itemgetter(0), data)
 
# display first elements
for i in first_data:
    print(i)

Output

Method 4: Using map() with Lambda Expression

Here we are using lambda expression along with map() function, here also we are using index 0 to get the first data.

Python3

# create tuples with college id
# and name and store in a list
data=[(1,'sravan'),(2,'ojaswi'),
      (3,'bobby'),(4,'rohith'),
      (5,'gnanesh')]
 
# map with lambda expression to get first element
first_data = map(lambda x: x[0], data)
 
# display data
for i in first_data:
    print(i)

Output

Method 5: Using List Comprehension

First create a list of tuples called data. Now use a List Comprehension to extract the first element of each tuple. Store it in a new list called result. Finally, it prints the result list.

Python3

# create tuples with college id and name and store in a list
data = [(1,'sravan'), (2,'ojaswi'), (3,'bobby'),(4,'rohith'),(5,'gnanesh')]
 
# Accessing first elements of each tuple
result = [t[0] for t in data]
print(result)

Output

[1, 2, 3, 4, 5]

Time complexity: O(n) (where n is the number of tuples in the list)
Auxiliary Space: O(n) (where n is the number of tuples in the list) since we are storing the result in a list.

We have provided you with 5 easy methods to get the first element from a list of tuples in Python. Accessing data from a data structure is a very basic operation and should be known if you are learning Python.

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