Python Tuples Explained With Code Samples

In my earlier article, I had covered Python Lists.  In this article, I will be covering Python tuples.

What is a Tuple

Just like a Python list, a tuple is a set of values.  Unlike a List, a tuple is immutable, so you cannot modify it after it is created. Also, the values in a List are enclosed in square brackets, a tuple on the other hand, uses parentheses.

Creating a Tuple

You can create a tuple by specifying comma separated values directly or within parentheses.  The following code demonstrates this:

mytuple1 = (1,"two",2.5,"three")

mytuple2 = 1,5,7

print(mytuple1)
print(mytuple2)

As you can see from the code above, a Python tuple can contain values of different data types. The above code creates a tuple mytuple1 that has values of type Integer, Decimal and String. It also creates mytuple2 using simple comma separated values. So this code prints the following output:

(1, 'two', 2.5, 'three')
(1, 5, 7)

Accessing values in a Tuple

You can access the values in a tuple via the slice operator. It consists of [] or [:]. You can access Python tuples both in the forward as well as backward direction.  In the forward direction,tuples start from position 0 for the first element in the tuple. In the backward direction, tuples start at position -1 for the last value in the list.

The following code demonstrates this:

mytuple = (2,4,'Hello',10.5,"World")
print (mytuple) 
print(mytuple[2]) 
print(mytuple[0:2]) 
print(mytuple[2:]) 
print(mytuple[:3])
print(mytuple[-1])

This code prints the following output:

(2, 4, 'Hello', 10.5, 'World')
Hello
(2, 4)
('Hello', 10.5, 'World')
(2, 4, 'Hello')
World

Updating a Tuple

As mentioned earlier, a tuple is immutable. So you cannot update a value from a tuple. If you try to update a value in a tuple, an error occurs. The following code demonstrates this:

mytuple = ("cat","dog","cow","monkey")
mytuple[2] = "horse"
print(mytuple)

This code tries to update the value at position 2. So an error occurs as follows:

Traceback (most recent call last):
File "tupledemo.py", line 20, in <module>
mytuple[2] = "horse"
TypeError: 'tuple' object does not support item assignment

Removing a value from a Tuple

You cannot delete an individual value from a tuple. However, you can delete the entire tuple. The following code demonstrates this:

mytuple = ("cat","dog","cow","monkey")
del mytuple
print(mytuple)

The above code deletes mytuple and then tries to print it. So it causes an exception as follows:

Traceback (most recent call last):
File "tupledemo.py", line 21, in <module>
print(mytuple)
NameError: name 'mytuple' is not defined

Concatenating Tuples

You can concatenate tuples using the concatenation operator(+ operator). The following code demonstrates this:

mytuple1 = ('apple','orange')
mytuple2 = ('banana','mango','cherry')

mytuple3 = mytuple1+mytuple2
print(mytuple3)

This code concatenates mytuple1 and mytuple2 and creates mytuple3 . So it prints the following output:

('apple', 'orange', 'banana', 'mango', 'cherry')

Using Repetition Operator

You can use the repetition operator(*) with tuples. The following code demonstrates this:

mytuple1 = ('apple','orange')
mytuple3 = mytuple1*3;
print(mytuple3)

This code creates a new tuple mytuple3 which repeats the contents of mytuple1 3 times. So it prints the following output:

('apple', 'orange', 'apple', 'orange', 'apple', 'orange')

Obtaining length of a tuple

Python has a built-in function len. This returns the length of the object passed in. You can use this function to obtain the length of a tuple. The following code demonstrates this:

mytuple1 = ('apple','orange')
print(len(mytuple1))

So this code prints the following output:

2

Further Learning

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Conclusion

So in this article, we understood what Python tuples are. We also understood how you can create a tuple, access an element from a tuple, concatenate tuples, use the repetition operator with tuples and obtain the length of a tuple. We also saw that tuples cannot be modified once they are created.