Mutable vs Immutable in Python|python tutorial for beginners 5 [2020]
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Mutable vs Immutable in Python|python tutorial for beginners 5 [2020]
Every variable in python holds an instance of an object. There are two types of objects in python i.e. Mutable and Immutable objects.
mutable objects can change their state or contents or values and immutable objects can’t change their state or content or values.
Immutable Objects : These are of in-built types like int, float, bool, string, unicode, tuple. In simple words, an immutable object can’t be changed after it is created.
x = 2
y = 2
x is y
x = 3 # didn't change x but define a new varialbe x refer to a new object
print(y) # y refer the old object 2
x= "hello"
y = x
x = 3
print(y)
print(x)
Let's try to modify the element of x.
x[0] = 'A'
TypeError: 'int' object does not support item assignment
Let's try to modify the content of a tuple:
t = (1,2,3)
t[0] = 10
TypeError: 'tuple' object does not support item assignment
But we can change the element of a list:
l = [1,2,3]
l[0] = 10
print(l)
How about this:
a = ([1,2,3],'hwdong')
a[0][2] = 20
print(a)
Although the element of a tuple can't be modified,but the elment of a tuple may be mutable.
mutable Objects : list、set、dict are mutable bulit-in types.
d = dict()
print(d)
d['hello'] = 3.14
print(d)
d['world'] = 'hwdong'
print(d)
d.pop('world',None)
print(d)
set
A set is a collection which is unordered and unindexed. In Python sets are written with curly brackets.
s= {'hello','world',3.14}
s.add(2)
print(s)
s.remove('world')
print(s)
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