| About | ordered | changeable | duplicate | Sample |
| list | ordered | changeable | allows | ['abc','def','abc'] |
| tuple | ordered | unchangeable | allows | ('abc','def','abc') |
| set | unordered | unindexed | Not allows | {'abc','def','ghi'} |
| dictionary | unordered | changeable | Not allows | {'name':'King','Class':'four'} |
Declaring a List
my_list=['Alex','Ronald','John']
print(my_list)
Output
['Alex','Ronald','John']
Displaying elements based on position
my_list=['Alex','Ronald','John']
print(my_list[2])
Output is here
John
index() : Returning the first position of the input element.
my_list=['Ronald','John','Alex','Ravi','Alex']
print(my_list.index('Alex'))
Output is here
2
The position starts from 0 and first element value is my_list[0], so the data at my_list[2] gives us John.
my_list=['Ronald','John','King','Ravi','Alex']
print(my_list[-1]) # last element will be displayed : Alex
print(my_list[-2]) # 2nd from last element will be displayed : Ravi
print(my_list[0:]) # All elements starting from 0 position till end.
print(my_list[:3]) # All elements starting from 0 position till 3.
print(my_list[1:4]) # All elements starting from 1 position till 4.
Output is here
Alex
Ravi
['Ronald', 'John', 'King', 'Ravi', 'Alex']
['Ronald', 'John', 'King']
['John', 'King', 'Ravi']
Displaying all items by looping
We used for loop to display all items of the list.
my_list=['Alex','Ronald','John']
for i in my_list:
print(i)
Output is here
Alex
Ronald
John
Add , remove , update elements
append()
my_list=['Alex','Ronald','John']
my_list.append('Ravi')
print(my_list)
Output is here
['Alex', 'Ronald', 'John', 'Ravi']
insert(): Adding at location
my_list=['Alex','Ronald','John']
my_list.insert(2,'Ravi')
print(my_list)
Output is here
['Alex', 'Ronald', 'Ravi', 'John']
extend() : Adding elements or list at the end of the list
my_list1=['Alex','Ronald','John']
my_list2=['Ravi','Alen']
my_list1.extend(my_list2)
print(my_list1)
Output is here
['Alex', 'Ronald', 'John', 'Ravi', 'Alen']
copy() : Creates new list by copying all elements
my_list1=['Alex','Ronald','John']
my_list2=my_list1.copy()
print(my_list2)
Output is here
['Alex', 'Ronald', 'John']
remove(): Deleting element
my_list=['Alex','Ronald','John']
my_list.remove('Ronald')
print(my_list)
Output is here
['Alex', 'John']
pop(): Deleting element based on location, by default it removes last element
my_list=['Alex','Ronald','John']
my_list.pop() # deletes last element
print(my_list)
Output is here
['Alex', 'Ronald']
We can remove element from a perticular position
my_list=['Alex','Ronald','John']
my_list.pop(0) # deletes first element
print(my_list)
Output is here
['Ronald', 'John']
We can collect the removed element
my_list=['Alex','Ronald','John']
name=my_list.pop(1) # deletes first element
print(name)
Output is here
Ronald
clear() : Removing all elements
my_list=['Alex','Ronald','John']
my_list.clear() # deletes all elements
print(my_list)
Output is here
[]
Searching element
my_list=['Alex','Ronald','John']
if 'John' in my_list:
print("Yes, included ")
else:
print("No, not included")
Output is here
Yes, included
Searching pair of numbers within a list
my_list=[[1,3],[3,4],[4,6]]
if [3,4] in my_list:
print("yes present")
else:
print("Not present")
output is here
yes present
Number of elements present:
count():Number of specified element present in a list ( counting the occurrence of a element )
my_list=['Alex','Ronald','John','Alex','Ravi','Alex']
print(my_list.count('Alex'))
Output is here
3
len() : Total Number of elements present in a list
my_list=['Alex','Ronald','John']
print("Number of elements:",len(my_list))
Output
Number of elements: 3
reverse() :Reverse the order of the list
my_list=['Ronald','John','Alex','Ravi']
my_list.reverse()
print(my_list)
Output
['Ravi', 'Alex', 'John', 'Ronald']
sort() : Sort the list in order
my_list=['Ronald','John','Alex','Ravi']
my_list.sort()
print(my_list)
Output
['Alex', 'John', 'Ravi', 'Ronald']
my_list=[4,2,7,1]
my_list.sort()
print(my_list)
Output is here
[1, 2, 4, 7]
Creating a list with distinct elements
We can use a set to store unique elements as set don't accept duplicate elements.
my_list=[1,2,3,4,4,5,5,6]
print(set(my_list))
Output
{1, 2, 3, 4, 5, 6}
Removing duplicate by using for loop
my_list=[1,2,3,4,4,5,5,6]
my_list2=[]
for i in my_list:
if i not in my_list2:
my_list2.append(i)
print(my_list2)
Output
[1, 2, 3, 4, 5, 6]
Getting unique elements and counting the occurrence by using Counter.
Sum of elements of a list
As list is an iterator Object , we can use sum to calculate sum of all elements.
my_list=[1,2,5,6]
my_list_sum=sum(my_list)
print(my_list_sum)
print("Sum by looping")
my_sum=0
for i in my_list:
my_sum=my_sum+i
print(my_sum)
Output
14
Sum by looping
14
Common elements between two Lists
list1=[3,2,5,8]
list2=[5,2,8,9]
print(set(list1) & set(list2))
Output
{8, 2, 5}
Highest and lowest Common elements
print(max(set(list1) & set(list2)))
print(min(set(list1) & set(list2)))
Output
8
2
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Matrix Multiplication without using built-in functions
Python- List append »