TUPLE
A Tuple is an ordered and unchangeable collection of python objects, each object is separated by a comma and the whole set is enclosed by parenthesis. Tuples allow duplicate values.
PROPERTIES OF TUPLE
Tuple items or objects are ordered, unchangeable, and allow duplicate values.
Tuple items are indexed, the first item has an index [0], the second item has an index [1], etc.
The items of a tuple are arbitrary Python objects. Tuples of two or more items are formed by comma-separated lists of expressions.
s = ('ABC', 100, 2.5)Sometimes the () is omitted in the syntax.
s = 'ABC', 100, 2.5A tuple of one item (a ‘singleton’) can be formed by affixing a comma to an expression (an expression by itself does not create a tuple, since parentheses must be usable for grouping of expressions).
t2 = ('ABC', ) # A 1-item tupleAn empty tuple can be formed by an empty pair of parentheses.
t1 = () # An empty tupleTUPLE UNPACKING
To use the tuple elsewhere, you can unpack its parts into variables.
name, quantity, price = s
print('Cost', quantity * price)
The number of variables on the left must match the tuple structure.
name, quantity = s # ERROR
Traceback (most recent call last):
...
ValueError: too many values to unpackTUPLE CONSTRUCTOR
tuple()–
It is also possible to use the tuple() constructor to make a tuple.
Example
Using the tuple() method to make a tuple:
Code
fruits = tuple(("apple", "banana", "cherry"))
print(fruits)Output
('apple', 'banana', 'cherry')MULTIPLY TUPLES
If you want to multiply the content of a tuple a given number of times, you can use the * operator:
Example
Multiply the fruits tuple by 2:
Code
fruits = ("apple", "banana", "cherry")
mytuple = fruits * 2
print(mytuple)Output
('apple', 'banana', 'cherry', 'apple', 'banana', 'cherry')TUPLE METHODS
Python has two built-in methods that you can use on tuples.
| Method | Description |
|---|---|
| count() | Returns the number of times a specified value occurs in a tuple |
| index() | Searches the tuple for a specified value and returns the position of where it was found |
HOW TO USE COUNT() IN PYTHON?
Code
a = (1, 3, 7, 8, 7, 5, 4, 6, 8, 5)
x = a.count(5) #returns no. of times 5 occurs in tuple a
print(x)Output
2HOW TO USE INDEX() IN PYTHON?
The index() method finds the first occurrence of the specified value.
The index() method raises an exception if the value is not found.
Code
#Search for the first occurrence of the value 7, and return its position:
a = (1, 3, 7, 8, 7, 5, 4, 6, 8, 5)
x = a.index(7)
print(x)Output
2DIFFERENCE BETWEEN TUPLE AND LIST
The difference between a tuple and a list is that a tuple is immutable whereas a list is mutable. We can store any type of data in Tuple.
Example of Tuple Syntax in Python-
| Code |
| a=(5,10) #values in the tuple are surrounded by parenthesis () print(a) #tuple is a collection of values b=(1,2.50,”hello”) #tuple as collection of different types of values print(b) #print tuple print(b[1]) #provide the value of 2nd element having index 1 print(len(b)) #provide the length print(b[0:2]) #slice the tuple |
| Output |
| (5, 10) (1, 2.5, ‘hello’) 2.5 3 (1, 2.5) |
Example of Immutability of Tuple-
b=(1,2.50,”hello”)
b[1]=4.50 #it will show error, as tuples are immutable
Example of type casting and concatenation of Tuple-
| Code |
| list1=[1,3.5,”hello”] #variable of list type list2=[4,2.1,8] #variable of list type print(list1) #printing variable list1 print(type(list1)) tuple1=tuple(list1) #type casting of list variable to tuple tuple2=tuple(list2) #type casting of list variable to tuple print(type(tuple1)) ctup=tuple1+tuple2 #concatinating tuple variables print(ctup) print(ctup[3]) #print 4th element,its immutable so ctup[3]=5 gives error a=(4) #it will be treated as expression having int value print(type(a)) #value of a is enclosed in () but missing comma a=(4,) #a singleton tuple is defined by adding comma as suffix print(type(a)) |
| Output |
| [1, 3.5, ‘hello’] <class ‘list’> <class ‘tuple’> (1, 3.5, ‘hello’, 4, 2.1, 8) 4 <class ‘int’> <class ‘tuple’> |
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