Python Tuple Operations

Table of Contents

In the last lesson, we learned about Python Introduction to Tuples. Now let’s join, repeat, search, and loop through tuples.

Let’s Do Things with Tuples

We know how to create a tuple. We know how to access items. We know that tuples are immutable.

But what can we actually do with them? What operations work on tuples?

Quite a lot, actually. We can join them. Repeat them. Check if something is inside. Find the smallest or largest. Count items. Find positions. And more.

Let’s go through the common tuple operations.

Joining Tuples with + in Python

We can join two tuples using the + operator. This is called concatenation.

tuple1 = (1, 2, 3)
tuple2 = (4, 5, 6)
combined = tuple1 + tuple2
print(combined)

Output

(1, 2, 3, 4, 5, 6)

It creates a new tuple with all the items from both tuples. The original tuples are not changed. Because tuples are immutable.

We can also use += to add to an existing variable.

tuple1 = (1, 2, 3)
tuple1 += (4, 5)
print(tuple1)

Output

(1, 2, 3, 4, 5)

This creates a new tuple and assigns it to tuple1. The old tuple is discarded.

Repeating a Tuple with * in Python

We can repeat a tuple using the * operator.

numbers = (1, 2)
repeated = numbers * 3
print(repeated)

Output

(1, 2, 1, 2, 1, 2)

It repeats the tuple the given number of times. Again, it creates a new tuple.

This is useful when we want to initialize a tuple with the same value multiple times.

zeros = (0,) * 5
print(zeros)

Output

(0, 0, 0, 0, 0)

But let’s be careful with mutable items. Tuples can contain lists, and repeating will share the same list reference. But that is an advanced topic. For now, let’s just know it works for simple values.

Checking Membership with in

We can check if an item is in a tuple using in.

colors = ("red", "green", "blue")
print("green" in colors)

Output

True

print("yellow" in colors)

Output

False

We can also use not in.

print("yellow" not in colors)

Output

True

Looping Through a Python Tuple

We can loop through a tuple just like a list.

colors = ("red", "green", "blue")
for color in colors:
    print(color)

Output

red
green
blue

We can also use enumerate() to get both index and value.

for index, color in enumerate(colors):
    print(f"{index}: {color}")

Output

0: red
1: green
2: blue

Finding the Length with len()

len() gives us the number of items in a tuple.

colors = ("red", "green", "blue")
print(len(colors))

Output

Finding the Smallest and Largest in a Python Tuple

Python has built-in functions min() and max() for tuples of comparable items.

numbers = (5, 2, 9, 1, 7)
print(min(numbers))
print(max(numbers))

Output

1
9

They also work on strings, comparing alphabetically.

words = ("banana", "apple", "cherry")
print(min(words))
print(max(words))

Output

apple
cherry

Adding Up Numbers with sum()

sum() adds up all the numbers in a tuple.

numbers = (1, 2, 3, 4, 5)
print(sum(numbers))

Output

It only works on numbers. If we try it on strings, we get an error.

Sorting with sorted() in Python

Tuples do not have a .sort() method. Because they are immutable. But we can use the built-in sorted() function. It returns a new list with the items sorted. The original tuple is unchanged.

numbers = (5, 2, 9, 1, 7)
sorted_numbers = sorted(numbers)
print(sorted_numbers)

Output

[1, 2, 5, 7, 9]

Notice the output is a list, not a tuple. If we want a sorted tuple, we can convert it.

sorted_tuple = tuple(sorted(numbers))
print(sorted_tuple)

Output

(1, 2, 5, 7, 9)

We can also sort in reverse.

print(sorted(numbers, reverse=True))

Output

[9, 7, 5, 2, 1]

The count() Method in Python Tuples

Tuples have a count() method. It tells us how many times a value appears.

numbers = (1, 2, 2, 3, 2, 4)
print(numbers.count(2))

Output

The index() Method in Python Tuples

Tuples have an index() method. It returns the index of the first occurrence of a value.

numbers = (1, 2, 3, 2, 4)
print(numbers.index(2))

Output

If the value is not found, it raises a ValueError.

numbers.index(10)   # Error!

So let’s check before using if we are not sure.

What We Cannot Do with Python Tuples

Because tuples are immutable, we cannot:

Add items with append() or extend()
Remove items with remove() or pop()
Sort in place with sort()
Reverse in place with reverse()
Change items with assignment

If we need any of these, we use a list instead. Or we convert the tuple to a list, make changes, and convert back.

t = (1, 2, 3)
lst = list(t)
lst.append(4)
t = tuple(lst)
print(t)

Output

(1, 2, 3, 4)

That is a common pattern.