List Operation in Python, List example in python

List Operation in Python:-

The list is a collection of items using proper sequence, It is similar to an array of another programming languages but the array contains a collection of similar type of elements but list contains a collection of the similar and dissimilar type of elements both.

The list provides an ordered collection of data, and it can store any type of element.

LIST provides a mutable object that means we can add, edit, and delete elements dynamically in the list.


Syntax of List:-

var = [item1,item2,item3,...]

x = [12,23]

Add element:-

x.append(24)   #[12,23,24]

Delete an element from LIST:-

del  x[0]

Modify List element:-

x[index]=value

LIST Program to implement all operation:-

x = ["vegetable","rice","fruit","oil","flour"]

#print(x[0],x[1],x[2],x[3],x[4])

for i in range(0,len(x)):

    print(x[i])

for value in x:

    print(value)

#to display a particular range

print(x[3:])

print(x[2:4])

print(x[-4:-1])

print(x[-4])

print(x[:3])

print(x[:])

x.append('noodles')

print(x)

del x[0]

print(x)

x[4] = 'maggi'

print(x)

    

Another Example of List to append, edit and delete elements using Python Program:-

x = [12,23,34,11,67,89]

x.append(101)  #append elements

del(x[0])  #delete element 

x[0]=120   #modify elements

for i in range(0,len(x)):

    print(x[i])

all arithmetic operation

Addition and multiplication using LIST:-

a= [1,2,3]
b = [4,5,6]

Addition:-

c=a+b    + is used to combine two list elements in one list

[1,2,3,4,5,6]

Multiplication:-

a*2         * it will repeat the list of elements


Program of LIST to implement addition, multiplication "IN" and "IS" operator:-

a=[1,2,3]
b=a*2
print(b)
x=[1,2,3]
y=[4,5,6]
z=x+y
print(z)
del x[0];
print(x)

if(20 in a):
    print("Found")
else:
    print("NOT found")

y=x
print(x)
print(y)
if(x is y):  #if same address then return true otherwise
    print("equall")
else:
    print("not equall")
    



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Multidimensional LIST:-

If we want to display elements under matrix format then we will use the Multi dimension List.

It is the collection of rows and columns.

x = [[1,2,3],[4,5,6]]
for i in range(0,2):
    for j in range(0,3):
        print(x[i][j],end=' ')
    print()   

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We can display Multidimension List using for...in the loop.

x = [[1,2,3,4,5],[3,4,6,7],[3,3,3]]

for i in x:

    for j in i:

        print(j,end='')

    print()    

How to take input from Users in LIST?

In most the cases, LIST type is used to contain composite data from the database or any external file.

but if we want to take input from user's then we can take it.

x = []  

size = int(input("number of elements")

for i in range(0,size):

  x.append(input("enter item"))

for i in range(0,len(x)):

  print(x[i])

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Assignments:-

1)  WAP to calculate the sum of List elements?

2)  WAP to display prime elements in LIST?

3)  WAP to divide one List into three different SubList?

4)  WAP to reverse LIST elements?

5)  WAP to combine three lists in one LIST?

6)  WAP to create marksheet using LIST with the same condition of IF-ELSE?

7)  WAP to display only unique elements in LIST?

8)  WAP to display repeated elements in LIST but it should display once?

9)  WAP to sort the LIST element in descending order?

10)  WAP to find max, second max, and third max elements in LIST without sorting?

Predefined in LIST:-

1) len():-  return size of list

2) append()

3)  extend()

4)  remove()

5)  cmp()

6) min()

7)  max()

8)  sort()

9)  reverse()

10) index()

11)  count()

12)  list()

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Example of List:-

x = [12,23,34,78,89,23,23,78]

print(len(x))

x.append(22)

print(x)

x.remove(23)

print(x)

x.index(12)

print(x.count(23))

y = [1,2,3]

#x=x+y

x.extend(y)

print(x)

x.sort()

print(x)

x.reverse()

print(x)

print(max(x))

print(min(x))

z = (1,2,3)

print(list(z))