Python list

PYTHON LIST
1).Python lists are the data structure that is capable of
holding different type of data.
2).Python lists are mutable i.e., Python will not create a
new list if we modify an element in the list.
3).It is a container that holds other objects in a given order.
Different operation like insertion and deletion can be
performed on lists.
4).A list can be composed by storing a sequence of
different type of values separated by commas.
5).A python list is enclosed between square([]) brackets.
6).The elements are stored in the index basis with starting
index as 0.

CREATING LIST
 A list can be created by putting the value inside the
square bracket and separated by comma.
 Syntax:
<list_name>=[value1,value2,value3,...,valuen];
 For accessing list :
<list_name>[index]

ELEMENTS IN A LISTS:
Data=[1,2,3,4,5];

LIST OPERATIONS:
a) Adding Lists:
Lists can be added by using the concatenation operator(+)
to join two lists.
Eg:
list1=[10,20]
list2=[30,40]
list3=list1+list2
print list3 Output:
>>>
[10, 20, 30, 40]
>>>

b) Replicating lists:
Replicating means repeating . It can be performed by
using '*' operator by a specific number of time.
Eg:
list1=[10,20]
print list1*1
Output:
>>>
[10, 20]
>>>

c) List slicing:
A subpart of a list can be retrieved on the basis of index.
This subpart is known as list slice.
Eg:
list1=[1,2,4,5,7]
print list1[0:2]
print list1[4]
list1[1]=9
print list1
Output:
>>>
[1, 2]
7
[1, 9, 4, 5, 7]
>>>

OTHER OPERATIONS:
a) Updating elements in a List:
To update or change the value of particular index of a list,
assign the value to that particular index of the List.
Syntax:
<list_name>[index]=<value>
Eg.
>>> list=[1,2,3,4]
>>> list[2]="Hello Python"
>>> print(list)
[1, 2, 'Hello Python', 4]
>>>

b) Appending elements to a List:
append() method is used to append i.e., add an element at
the end of the existing elements.
Syntax:
<list_name>.append(item)
Eg.
>>> list=[1,2,3,4]
>>> list.append(40)
>>> print(list)
[1, 2, 3, 4, 40]
>>>

c) Deleting Elements from a List:
del statement can be used to delete an element from the
list. It can also be used to delete all items from
startIndex to endIndex.
Eg.
>>> list = [1,2,3,4]
>>> del list[2]
>>> print(list)
[1, 2, 4]

FUNCTIONS AND METHODS OF LISTS:
Function Description Example
min(list)
Returns the minimum
value from the list
given.
>>> list=[1,2,3,4,5]
>>> min(list)
1
max(list)
Returns the largest
value from the given
list.
>>> list=[1,2,3,4,5]
>>> max(list)
5
len(list)
Returns number of
elements in a list.
>>> list=[1,2,3,4,5]
>>> len(list)
5

Methods Description Example
index(object)
Returns the index value of the
object.
>>> l = ['a','b','c','d']
>>>l.index(‘a’)
>>>0
count(object)
It returns the number of times an
object is repeated in list.
>>> l = [1,2,3,1,4,5,1]
>>> l.count(1)
3
pop()/pop(index)
Returns the last object or the
specified indexed object. It
removes the popped object.
>>> l = [1,2,3,1,4,5,1]
>>> l.pop()
1
>>> print(list)
[1, 2, 3, 4, 5]
>>> l.pop(3)
1
>>> print(l)
[1, 2, 3, 4, 5]

Methods Description Example
insert(index,object)
Insert an object at the
given index.
>>>l=[1,2,3,4,5]
>>> l.insert(3,11)
>>> print(l)
[1, 2, 3, 11, 4, 5]
extend(sequence)
It adds the sequence to
existing list.
>>>l=[1, 2, 3, 11, 4, 5]
>>> seq = (12,13)
>>> l.extend(seq)
>>> print(l)
[1, 2, 3, 11, 4, 5, 12, 13]
remove(object)
It removes the object
from the given List.
>>>l=[1, 2, 3, 11, 4, 5, 12,
13]
>>> l.remove(12)
>>> print(l)
[1, 2, 3, 11, 4, 5, 13]

Methods Description
Example
reverse()
Reverse the position of all the
elements of a list.
>>>l=[1, 2, 3, 11, 4, 5, 13]
>>> l.reverse()
>>> print(l)
[13, 5, 4, 11, 3, 2, 1]
sort()
It is used to sort the elements
of the List.
>>> l = [2,4,1,5,3]
>>> l.sort()
>>> print(l)
[1, 2, 3, 4, 5]

Python list

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