LIST IN PYTHON AND SOME COMMON FUNCTIONS USED IN THE EXAMPLE

List : list is used to represent group of elements into a single entity or object. Insertion order is preserved. Duplicate elements are allowed. Heterogeneous elements are allowed. Every element in the list object is represented with unique index. List supports both positive and negative indexes. We can perform the operations on the elements of the list object by using ‘indexes’. We can create the list object by using ‘list()’ function and by using square brackets ‘[ ]’. List objects are mutable objects.

Example –

a=[]
print a
print type(a)
b=[10,20,30]
print b
print type(b)
x=list()
print x
print type(x)
y=list('rakesh')
print y
print type(y)

Output –

[]

<type 'list'>

[10, 20, 30]

<type 'list'>

[]

<type 'list'>

['r', 'a', 'k', 'e', 's', 'h']

<type 'list'>

Example –

x=[10,20,'rakesh',True,123.123,10,'rakesh']
print x
print id(x)
y=[10,20,30,40,50]
print y
print id(y)
print y[2]
print y[2:4]
print y[-2]
print y[0:-3]
y[2]=100
print y
print id(y)
del y[3]
print y
print id(y)

Output –

[10, 20, 'rakesh', True, 123.123, 10, 'rakesh']

43452136

[10, 20, 30, 40, 50]

43452456

30

[30, 40]

40

[10, 20]

[10, 20, 100, 40, 50]

43452456

[10, 20, 100, 50]

43452456

Example –

x=[100,123.123,'rakesh']
print x
print len(x)
a,b,c=x
print a
print type(a)
print b
print type(b)
print c
print type(c)
y=[10,20,[100,200,300],'rakesh']
print y

Output –

[100, 123.123, 'rakesh']

3

100

<type 'int'>

123.123

<type 'float'>

rakesh

<type 'str'>

[10, 20, [100, 200, 300], 'rakesh']

Example –

x=['rakesh','guwahati','assam']
print x
for p in x:
    print p,'---->',len(p)
    for q in p:
        print q

Output –

['rakesh', 'guwahati', 'assam']

rakesh ----> 6

r

a

k

e

s

h

guwahati ----> 8

g

u

w

a

h

a

t

i

assam ----> 5

a

s

s

a

m

Example –

x=[[10,20,30],[40,50,60],[70,80,90]]
print x
for p in x:
    for q in p:
        print q,
    print

Output –

[[10, 20, 30], [40, 50, 60], [70, 80, 90]]

10 20 30

40 50 60

70 80 90

Example –

x=[10,20,30]
print x
print id(x)
y=[10,20,30]
print y
print id(y)
print x==y
print x is y
z=y
print z
print id(z)
print y==z
print y is z

Output –

[10, 20, 30]

35718888

[10, 20, 30]

35719208

True

False

[10, 20, 30]

35719208

True

True

Example –

x=[10,20,30,40,50]
print x
print id(x)
print len(x)
x.append(60)
print x
print id(x)
x.insert(2,70)
print x
y=['abc','def','xyz',30]
print y
x.extend(y)
print x
print x.index('abc')
x.remove(30)
print x
x.sort()
print x.pop()
print x
x.pop(3)
print x
print id(x)

Output –

[10, 20, 30, 40, 50]

38274792

5

[10, 20, 30, 40, 50, 60]

38274792

[10, 20, 70, 30, 40, 50, 60]

['abc', 'def', 'xyz', 30]

[10, 20, 70, 30, 40, 50, 60, 'abc', 'def', 'xyz', 30]

7

[10, 20, 70, 40, 50, 60, 'abc', 'def', 'xyz', 30]

xyz

[10, 20, 30, 40, 50, 60, 70, 'abc', 'def']

[10, 20, 30, 50, 60, 70, 'abc', 'def']

38274792