Introduction to different types of Python Tuples

If you are interested to learn about the python lists

A tuple is a collection of objects which ordered and immutable. Tuples are used to store multiple items in a single variable. Tuple is one of 4 built-in data types in Python used to store collections of data, the other 3 are List, Set, and Dictionary, all with different qualities and usage. A tuple is a collection which is ordered and unchangeable.Tuples are sequences, just like lists. The differences between tuples and lists are, the tuples cannot be changed unlike lists and tuples use parentheses, whereas lists use square brackets .Creating a tuple is as simple as putting different comma-separated values. Optionally you can put these comma-separated values between parentheses also. For example −

tup1 = ('physics', 'chemistry', 1997, 2000);
tup2 = (1, 2, 3, 4, 5 );
tup3 = "a", "b", "c", "d";

The empty tuple is written as two parentheses containing nothing −

tup1 = ();

To write a tuple containing a single value you have to include a comma, even though there is only one value −

tup1 = (50,);

Like string indices, tuple indices start at 0, and they can be sliced, concatenated, and so on.

Tuple Items

Tuple items are ordered, unchangeable, and allow duplicate values.

Tuple items are indexed, the first item has index [0], the second item has index [1] etc.

Ordered

When we say that tuples are ordered, it means that the items have a defined order, and that order will not change.

Unchangeable

Tuples are unchangeable, meaning that we cannot change, add or remove items after the tuple has been created.

Allow Duplicates

Since tuples are indexed, they can have items with the same value:

Example

Tuples allow duplicate values:

thistuple = ("apple", "banana", "cherry", "apple", "cherry")<br>print(thistuple)

Tuple Length

To determine how many items a tuple has, use the len() function:

Example

Print the number of items in the tuple:

thistuple = ("apple", "banana", "cherry")<br>print(len(thistuple))

Create Tuple With One Item

To create a tuple with only one item, you have to add a comma after the item, otherwise Python will not recognize it as a tuple.

Example

One item tuple, remember the comma:thistuple = (“apple”,)
print(type(thistuple))

#NOT a tuple<br>thistuple = ("apple")<br>print(type(thistuple))

Tuple Items – Data Types

Tuple items can be of any data type:

Example

String, int and boolean data types:

tuple1 = ("apple", "banana", "cherry")<br>tuple2 = (1, 5, 7, 9, 3)<br>tuple3 = (True, False, False)

A tuple can contain different data types:

Example

A tuple with strings, integers and boolean values:

tuple1 = ("abc", 34, True, 40, "male")

type()

From Python’s perspective, tuples are defined as objects with the data type ‘tuple’:<class ‘tuple’>

Example

What is the data type of a tuple?

mytuple = ("apple", "banana", "cherry")<br>print(type(mytuple))

The tuple() Constructor

It is also possible to use the tuple() constructor to make a tuple.

Example

Using the tuple() method to make a tuple:

thistuple = tuple(("apple", "banana", "cherry")) # note the double round-brackets<br>print(thistuple)

Accessing Values in Tuples

To access values in tuple, use the square brackets for slicing along with the index or indices to obtain value available at that index. For example −

#!/usr/bin/python

tup1 = ('physics', 'chemistry', 1997, 2000);
tup2 = (1, 2, 3, 4, 5, 6, 7 );
print "tup1[0]: ", tup1[0];
print "tup2[1:5]: ", tup2[1:5];

When the above code is executed, it produces the following result −

tup1[0]:  physics
tup2[1:5]:  [2, 3, 4, 5]

Updating Tuples

Tuples are immutable which means you cannot update or change the values of tuple elements. You are able to take portions of existing tuples to create new tuples as the following example demonstrates −

#!/usr/bin/python

tup1 = (12, 34.56);
tup2 = ('abc', 'xyz');

# Following action is not valid for tuples
# tup1[0] = 100;

# So let's create a new tuple as follows
tup3 = tup1 + tup2;
print tup3;

When the above code is executed, it produces the following result −

(12, 34.56, 'abc', 'xyz')

Delete Tuple Elements

Removing individual tuple elements is not possible. There is, of course, nothing wrong with putting together another tuple with the undesired elements discarded.

To explicitly remove an entire tuple, just use the del statement. For example −

#!/usr/bin/python

tup = ('physics', 'chemistry', 1997, 2000);
print tup;
del tup;
print "After deleting tup : ";
print tup;

This produces the following result. Note an exception raised, this is because after del tup tuple does not exist any more −

('physics', 'chemistry', 1997, 2000)
After deleting tup :
Traceback (most recent call last):
   File "test.py", line 9, in &lt;module&gt;
      print tup;
NameError: name 'tup' is not defined

Basic Tuples Operations

Tuples respond to the + and * operators much like strings; they mean concatenation and repetition here too, except that the result is a new tuple, not a string. In fact, tuples respond to all of the general sequence operations we used on strings in the prior chapter −

Python ExpressionResultsDescription
len((1, 2, 3))3Length
(1, 2, 3) + (4, 5, 6)(1, 2, 3, 4, 5, 6)Concatenation
(‘Hi!’,) * 4(‘Hi!’, ‘Hi!’, ‘Hi!’, ‘Hi!’)Repetition
3 in (1, 2, 3)TrueMembership
for x in (1, 2, 3): print x,1 2 3Iteration

Indexing, Slicing, and Matrixes

Because tuples are sequences, indexing and slicing work the same way for tuples as they do for strings. Assuming following input −

L = ('spam', 'Spam', 'SPAM!')
Python ExpressionResultsDescription
L[2]‘SPAM!’Offsets start at zero
L[-2]‘Spam’Negative: count from the right
L[1:][‘Spam’, ‘SPAM!’]Slicing fetches sections

No Enclosing Delimiters

Any set of multiple objects, comma-separated, written without identifying symbols, i.e., brackets for lists, parentheses for tuples, etc., default to tuples, as indicated in these short examples −

#!/usr/bin/python

print 'abc', -4.24e93, 18+6.6j, 'xyz';
x, y = 1, 2;
print "Value of x , y : ", x,y;

When the above code is executed, it produces the following result −

abc -4.24e+93 (18+6.6j) xyz
Value of x , y : 1 2

Python – Access Tuple Items

Access Tuple Items

You can access tuple items by referring to the index number, inside square brackets:

Example

Print the second item in the tuple:

thistuple = ("apple", "banana", "cherry")
print(thistuple[1])

Negative Indexing

Negative indexing means start from the end.

-1 refers to the last item, -2 refers to the second last item etc.

Example

Print the last item of the tuple:

thistuple = ("apple", "banana", "cherry")
print(thistuple[-1])

Range of Indexes

You can specify a range of indexes by specifying where to start and where to end the range. When specifying a range, the return value will be a new tuple with the specified items.

Example

Return the third, fourth, and fifth item:

thistuple = ("apple", "banana", "cherry", "orange", "kiwi", "melon", "mango")
print(thistuple[2:5])

Python – Update Tuples

Tuples are unchangeable, meaning that you cannot change, add, or remove items once the tuple is created. But there are some workarounds.

Change Tuple Values

Once a tuple is created, you cannot change its values. Tuples are unchangeable But there is a workaround. You can convert the tuple into a list, change the list, and convert the list back into a tuple.

Example

Convert the tuple into a list to be able to change it:

x = ("apple", "banana", "cherry")
y = list(x)
y[1] = "kiwi"
x = tuple(y)

print(x)

Python – Unpack Tuples

Unpacking a Tuple

When we create a tuple, we normally assign values to it. This is called “packing” a tuple:

Example

Packing a tuple:

fruits = ("apple", "banana", "cherry")

But, in Python, we are also allowed to extract the values back into variables. This is called “unpacking”:

Example

Unpacking a tuple:

fruits = ("apple", "banana", "cherry")

(green, yellow, red) = fruits

print(green)
print(yellow)
print(red)

Python – Loop Tuples

Loop Through a Tuple

You can loop through the tuple items by using a for loop.

Example

Iterate through the items and print the values:

thistuple = ("apple", "banana", "cherry")
for x in thistuple:
  print(x)

Loop Through the Index Numbers

You can also loop through the tuple items by referring to their index number. Use the range() and len() functions to create a suitable iterable.

Example

Print all items by referring to their index number:

thistuple = ("apple", "banana", "cherry")
for i in range(len(thistuple)):
  print(thistuple[i])
Introduction to different types of Python Tuples
Show Buttons
Hide Buttons