Python Tuples (With Examples)

Tuples are a simple group of objects. Similar to lists, Tuples can also store different objects. Tuples in Python are written as a series of items/objects in a parenthesis.

Topics Covered

1. Characteristics of Tuples
2. How to create a tuple in Python?
3. Concatenating Tuples
4. Access elements of a tuple
5. Slicing of Tuples
   • Slicing Tuples with Positive Index
   • Slicing Tuple with Negative Index
   • Mixing positive and negative indices for slicing tuples
   • Using steps in slicing
   • Reversing a tuple
6. Deleting a tuple
7. Commonly used methods with tuples
   • How to sort tuples?
   • count() and index()
8. Tuple Swap
   • How Tuple Swap works?
9. Lists vs Tuples
10. Problems to solve

Characteristics of Tuples

1. Similar to strings and lists, tuples are ordered collections of objects. They maintain a left-to-right order of their content.
2. Similar to lists, they can store different kinds of objects.
3. Similar to strings and lists, the object(s) in the tuple can be accessed by their index or slicing.
4. Similar to strings, Tuples are immutable. They don’t support any in-place change operations.
5. Because tuples are immutable, you cannot change the size of a tuple without making a copy.

How to create a tuple in Python?

Below are various ways to create different types of tuples in Python.

Code

# Empty Tuple
x = ()
print(x)

# One item Tuple
x = (1,) # Notice the trailing comma
print(x)

# Multiple items tuple
x = (1, 2, 3, 4)
print(x)

# Nested Tuples
x = ((1, 2), 3, 4)
print(x)

# Tuple from a list
x = tuple([1, 2, 3, 4])
print(x)

# Tuple from a string
x = tuple('Pylenin')
print(x)

# Tuple from a dictionary
x = tuple({"name":"Pylenin", "language":"Python"})
print(x)

Output

()
(1,)
(1, 2, 3, 4)
((1, 2), 3, 4)
(1, 2, 3, 4)
('P', 'y', 'l', 'e', 'n', 'i', 'n')
('name', 'language')

You can also create tuples without using parenthesis.

Code

x = 1, 2, 3, 4

print(x)

Output

(1, 2, 3, 4)

In the context of the above assignment statement, Python recognizes this as a tuple, even though it doesn’t have parentheses.

Syntax peculiarity of Tuples

To create a single element tuple, make sure to add a trailing comma. Otherwise, Python will treat it as an individual data type.

Code

x = ("Pylenin")
print(type(x))

x = ("Pylenin",)
print(type(x))

Output

<class 'str'>
<class 'tuple'>

Concatenating Tuples

Similar to strings and lists, you can use the + or * operator to concatenate lists.

Code

# Using + operator
x = (1, 2, 3)
y = (4,)
x += y
print("x is now ", x)

# Using * operator
x = (1, 2, 3)
x *= 2
print("x is now ", x)

Output

x is now  (1, 2, 3, 4)

x is now  (1, 2, 3, 1, 2, 3)

Notice how the ids have changed after both concatenation operations.

Access elements of a tuple

The process of accessing elements from a tuple, works similar to strings and lists.

You can access individual elements of a tuple using indexing and a range of elements using slicing. In Python tuples, index starts from 0 and keeps increasing by 1 with every element in the tuple. This is called Positive Indexing(or indexing from the beginning). If there are n elements in a tuple, the 1st element will have index of 0 and the last element will have index n-1.

Python also allows negative indexing of tuples(indexing from the end). If there are n elements in a list, the last element will have index of -1 and the first element will have index -n.

Let’s look at the image below for better understanding.

Code

my_tuple = (1, 2, 3, 4, 5)

# first character
print('my_tuple[0] =', my_tuple[0])

# last character
print('my_tuple[-1] =', my_tuple[-1])

# second character
print('my_tuple[1] =', my_tuple[1])

# second last character
print('my_tuple[-2] =', my_tuple[-2])

Output

my_tuple[0] = 1
my_tuple[-1] = 5
my_tuple[1] = 2
my_tuple[-2] = 4

If you try to access an element out of range, it will raise an IndexError.

Also, the index must be an integer. You can’t use floats or other types for indexing. This will result in TypeError.

Code/Output

my_tuple = (1, 2, 3, 4, 5)

print(my_tuple[10])
>>> IndexError: list index out of range

print(my_tuple[3.5])
>>> TypeError: tuple indices must be integers or slices, not float

Slicing of Tuples

Similar to strings and lists, you can access a range of elements from a tuple using slicing.

Basically, you have to specify the starting index and the end index, separated by a colon(:), to return a range of elements from the tuple.

Slicing Tuples with Positive Index

Remember - The last index is not included.

Let’s say you want to access the 1st and the 2nd index from a tuple. In that case, your end index will be 3.

Code

my_tuple = (1, 2, 3, 4, 5)

print(my_tuple[1:3])

Output

(2, 3)

If you leave out the start index, the range will start at the first element.

Code

my_tuple = (1, 2, 3, 4, 5)

# leave out the first index
print(my_tuple[:3])

Output

(1, 2, 3)

If you leave out the end index, the range will go to the end.

Code

my_tuple = (1, 2, 3, 4, 5)

# leave out the end index
print(my_tuple[1:])

Output

(2, 3, 4, 5)

So, if you leave out both the start and end index, you will get a replica of the original tuple.

Code

my_tuple = (1, 2, 3, 4, 5)

# leave out the start and end index
print(my_tuple[:])

Output

(1, 2, 3, 4, 5)

Slicing Tuple with Negative Index

You can also use negative index for slicing. Just use the negative index counterpart of your positive index to slice a tuple.

Code

my_tuple = (1, 2, 3, 4, 5)

# Slicing with Positive Index
print(my_tuple[1:3])
# Slicing with Negative Index
print(my_tuple[-4:-2])

Output

(2, 3)
(2, 3)

Mixing positive and negative indices for slicing tuples

You can also mix positive and negative indices while slicing a tuple.

Code

my_tuple = (1, 2, 3, 4, 5)

print(my_tuple[1:-1])
print(my_tuple[-3:5])

Output

(2, 3, 4)
(3, 4, 5)

Let’s understand the above example using the below image.

Using steps in slicing

You can also include steps while slicing a tuple. The step allows you to take every nth element while slicing.

Syntax

tuple[start:stop:step]

Code

my_tuple = (1, 2, 3, 4, 5)

# Get every second element
# from beginning to end
print(my_tuple[::2])

# Get every second element
# starting at index 1 till end
print(my_tuple[1::2])

# Get every second element
# starting at index 1 upto -2 index
print(my_tuple[1:-2:2])

Output

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

Reversing a tuple

Negative step changes the slice to be built from the tail of the tuple. So, it goes from the last element to the first element. This way, we get a reversed tuple.

Code

my_tuple = (1, 2, 3, 4, 5)

print(my_tuple[::-1])

Output

(5, 4, 3, 2, 1)

When using a negative step, the start and stop values have to be provided from right to left (usually it is from left to right).

Code

my_tuple = (1, 2, 3, 4, 5)

# Reverse the list
# without the last element
print(my_tuple[-2::-1])

# Reverse the list
# without the first and last element
print(my_tuple[-2:0:-1])

Output

(4, 3, 2, 1)
(4, 3, 2)

Deleting a tuple

Because tuples are immutable, you cannot delete specific elements of a tuple

Code

my_tuple = (1, 2, 3, 4, 5)

del my_tuple[0]

Output

TypeError: 'tuple' object doesn't support item deletion

However, it is possible to delete the entire tuple object.

Code

my_tuple = (1, 2, 3, 4, 5)

del my_tuple
print(my_tuple)

Output

NameError: name 'my_tuple' is not defined

Commonly used methods with tuples

How to sort tuples?

Python doesn’t provide all the methods that come with lists, strings or dictionaries. For example, if you want to sort a tuple in increasing or decreasing order, you have to first convert it into a mutable object like list to get access to sorting methods.

Code

my_tuple = (1, 2, 3, 4, 5)

my_list = list(my_tuple)

# sort in ascending order
my_list.sort()
print(tuple(my_list))

# sort in descending order
my_list.sort(reverse=True)
print(tuple(my_list))

Output

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

count() and index()

Similar to lists, you can also count the index and number of occurrences of an element in tuple.

Code

my_tuple = (1, 2, 3, 4, 5)

print(my_tuple.count(1))
print(my_tuple.index(1))

Output

1
0

Tuple Swap

Let’s say you want to interchange the values of two variables.

Ideally, you would need a 3rd temporary variable to achieve the objective.

Code

x = 10
y = 20
# Create a temp variable z
z = x
x = y
y = z

print(x, y)

Output

20 10

However, you can easily do this with Python without creating a 3rd temporary variable. The underlying concept is called a Tuple Swap.

Code

x = 10
y = 20

x, y = y, x
print(x, y)

Output

20 10

How Tuple Swap works?

Let’s understand the mechanism behind Tuple Swap.

We know from the section on creating tuples that, Python can create a tuple without parenthesis.

Code

x = 1, 2, 3
print(x)

Output

(1, 2, 3)

Now notice the below code.

LHS    RHS
x, y = y, x

Python considers the y, x part as a tuple. It sees it as (20, 10).

So the above assignment changes to x, y = (20, 10)

Now, Python unpacks the iterable into values of x and y.

So the values become interchanged. Check out this article on unpacking iterables in Python to see how unpacking works.

Lists vs Tuples

The major difference between lists and tuples is that tuples are immutable. So a tuple can’t be changed through another reference elsewhere in the program. However, lists can be altered at any stage of the program.

There are also other noticeable differences like:-

1. Tuples can’t be copied. tuple(my_tuple) returns you the same tuple. Lists can be copied.
2. Tuples occupy a smaller memory compared to lists as they are immutable. This makes tuples a bit faster.
3. Tuples are of fixed lengths. So you can’t add or remove elements from a tuple.
4. You can’t apply a lot of methods on Tuples. For example - To sort, you first have to convert a tuple to list.

If you’re defining a constant set of values on which you are only going to iterate through, use a tuple instead of a list. You can always convert it to a list later, when you need to.

Problems

1. Change the values of the below variables without using a 3rd variable.

   x = "Apple"
   y = "Banana"
   

2. Sort the below tuple in increasing order of the length of each element.

   my_tuple = ("Pylenin", "loves", "Python")
   

3. Convert the keys and values of the dictionary to tuple.

   my_dict = {"name" : "Pylenin",
              "verb" : "loves",
              "object": "Python"}
   
   Result ==> (("name", "Pylenin"), ("verb", "loves"), ("object", "Python"))