Find the index of a tuple in a list in Python

Find the index of a tuple in a list in Python #

To find the index of a tuple in a list:

Use the enumerate function to get an iterable with the indices and tuples.
Use a list comprehension to iterate over the iterable.
Return a condition on each iteration.

main.py

Copied!
list_of_tuples = [(5, 'Alice'), (10, 'Bob'), (15, 'Carl'), (20, 'Dean')]

# 👇️ [(0, (5, 'Alice')), (1, (10, 'Bob')), (2, (15, 'Carl')), (3, (20, 'Dean'))]
print(list(enumerate(list_of_tuples)))

# ✅ get list of all indices of tuples that match the condition

result = [
    idx for idx, tup in enumerate(list_of_tuples) if tup[1] == 'Carl'
]

print(result)  # 👉️ [2]

print(list_of_tuples[result[0]])  # 👉️ (15, 'Carl')

# --------------------------------------------------

# ✅ get the index of the first tuple that matches the condition

result_1 = [tup[1] for tup in list_of_tuples].index('Carl')

print(result_1)  # 👉️ 2

The enumerate function takes an iterable and returns an enumerate object containing tuples where the first element is the index, and the second - the item.

main.py

Copied!
list_of_tuples = [(5, 'Alice'), (10, 'Bob'), (15, 'Carl'), (20, 'Dean')]

# 👇️ [(0, (5, 'Alice')), (1, (10, 'Bob')), (2, (15, 'Carl')), (3, (20, 'Dean'))]
print(list(enumerate(list_of_tuples)))

We used a list comprehension to iterate over the iterable.

main.py

Copied!
list_of_tuples = [(5, 'Alice'), (10, 'Bob'), (15, 'Carl'), (20, 'Dean')]

# 👇️ [(0, (5, 'Alice')), (1, (10, 'Bob')), (2, (15, 'Carl')), (3, (20, 'Dean'))]
print(list(enumerate(list_of_tuples)))

# ✅ get list of all indices of tuples that match the condition

result = [
    idx for idx, tup in enumerate(list_of_tuples) if tup[1] == 'Carl'
]

print(result)  # 👉️ [2]

print(list_of_tuples[result[0]])  # 👉️ (15, 'Carl')

List comprehensions are used to perform some operation for every element, or select a subset of elements that meet a condition.

On each iteration, we check if the tuple element at index 1 is equal to the string Carl.

If the condition is met, we return the corresponding index.

When using this approach, we get a list of all of the tuple indexes for which the condition is satisfied.

If you need to only get the first tuple index for which the condition is met, use a list comprehension and the index() method.

To find the index of a tuple in a list:

Use a list comprehension to iterate over the list of tuples.
On each iteration, return the tuple item you want to check for.
Use the list.index() method to get the index of the first tuple with the specified value.

main.py

Copied!
list_of_tuples = [(5, 'Alice'), (10, 'Bob'), (15, 'Carl'), (20, 'Dean')]


result_1 = [tup[1] for tup in list_of_tuples].index('Carl')

print(result_1)  # 👉️ 2

The first step is to use a list comprehension to get a list of primitives from a list of tuples.

main.py

Copied!
list_of_tuples = [(5, 'Alice'), (10, 'Bob'), (15, 'Carl'), (20, 'Dean')]


# 👇️ ['Alice', 'Bob', 'Carl', 'Dean']
print([tup[1] for tup in list_of_tuples])

On each iteration, we return the tuple element at index 1.

Make sure to adjust this depending on your use case.

The last step is to use the list.index() method to get the index of the value in the list.

The list.index() method returns the index of the first item whose value is equal to the provided argument.

main.py

Copied!
my_list = ['apple', 'banana', 'kiwi']

result = my_list.index('banana')

print(result)  # 👉️ 1

The method raises a ValueError if there is no such item in the list.

Use this approach if you only need the index of the first tuple in the list for which the condition is satisfied.

Find the index of a tuple in a list in Python

Find the index of a tuple in a list in Python #

Borislav Hadzhiev