Tuple

A tuple is a sequence of immutable Python objects. A tuple contains heterogeneous datatype.

Basic Syntax of declaring tuple is

t1 = (23 , 'tuple' )          from parentheses we know it is tuple

  
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

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 

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:

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 <module>
    print tup;
NameError: name 'tup' is not defined

Built-in Tuple Functions

Python includes the following tuple functions

1. cmp(tuple1, tuple2)

    Compares elements of both tuples
2. len(tuple)

    Gives the total length of the tuple

3. max(tuple)

    Returns item from the tuple with max value

4.  min(tuple)

     Returns item from the tuple with min value

5.  tuple(seq)

     Converts a list into tuple