Day 23 - List and List functions

List:

List is represented by
List is a collection of heterogeneous data(Different datatype).
List is index_based
List is mutable(changeable)

Example:

student_data = ['Pritha', 'B.E', 30, True, 5.6]
print(student_data)

['Pritha', 'B.E', 30, True, 5.6]

Example using while loop:

student_data = ['Pritha', 'B.E', 30, True, 5.6]
i = 0 
while i<len(student_data):
    print(student_data[i],end=' ')
    i+=1

Pritha B.E 30 True 5.6

Example using for loop:

student_data = ['Pritha', 'B.E', 30, True, 5.6]
for data in student_data:
    print(data, end=" ")

Pritha B.E 30 True 5.6

enumerate():

It is used to create the index in the loop.
Also used for grouping and index tracking.

student_data = ['Pritha', 'B.E', 30, True, 5.6]
index = 0
for index,data in enumerate(student_data):
    print(index, data)
    index+=1

0 Pritha
1 B.E
2 30
3 True
4 5.6

List is mutable so we can change any element from the list.

student_data = ['Pritha', 'B.E', 30, True, 5.6]
print(student_data)

student_data[1] = 'M.E'
print(student_data)

['Pritha', 'B.E', 30, True, 5.6]
['Pritha', 'M.E', 30, True, 5.6]

append():

It is used to add an element to the end of a list.
It modifies the list in-place and does not return a new list.

Create a list using append():

employee = []
employee.append('Raja')
employee.append('Madurai')
employee.append('B.Sc.,')
employee.append(5.2)
employee.append(True)

print(employee)

['Raja', 'Madurai', 'B.Sc.,', 5.2, True]

insert():

It is used to insert an element at a specific position in a list.

employee = ['Raja', 'Madurai', 'B.Sc.,', 5.2, True]
employee.insert(2, 'Tamil Nadu')
print(employee)

['Raja', 'Madurai', 'Tamil Nadu', 'B.Sc.,', 5.2, True]

remove():

It is used to remove the first occurrence of a specific element from a list.
If the element is found, it is removed, and the list is modified in place.
If the element is not present in the list, a ValueError is raised.

employee = ['Raja', 'Madurai', 'B.Sc', 5.2, True]
employee.remove('Madurai')
print(employee)

['Raja', 'B.Sc', 5.2, True]

pop():

It is used to remove and return an element from a list at a specific index.

employee = ['Raja', 'Madurai', 'B.Sc', 5.2, True]
employee.pop(3) 
print(employee)

['Raja', 'Madurai', 'B.Sc', True]

del statement:

It is used to delete an element from a list by index.
It does not return a value; it simply removes the item or object from memory.

l = [10,20,30,40,50,60]
del l[2]
print(l)

[10, 20, 40, 50, 60]

We can use del to remove an item from a list by specifying a slice.

l = [10,20,30,40,50,60]
del l[2:4]
print(l)

[10, 20, 50, 60]

Difference between pop() and del:

l = [10,20,30,40,50,60]
del l[:]
print(l)
l = [10,20,30,40,50,60]
print(l.pop())

[]
60

del[:]- Delete everything from the list
pop()- Delete last element from the list.

Write a program to calculate total mark and percentage:

marks_list = [90,97,97,65,78]
total = 0
l=len(marks_list)
for mark in marks_list:
    total+=mark 
print(total)

percentage=total/l
print("percentage:",percentage)

427
percentage: 85.4

Write a Program to find the highest mark from the given mark:

highest = 0
marks_list = [90,97,96,65,98]

for mark in marks_list:
    if mark>highest:
        highest = mark #90 97 

print(highest)

98

Write a program to find the lowest mark from the given mark:

lowest = 100
marks_list = [90,97,96,65,98]

for mark in marks_list:
    if mark<lowest:
        lowest = mark 

print(lowest)

65

scores = [90,167, 208,45,32]
lowest = scores[0]

for score in scores:
    if score<lowest:
        lowest = score 

print(lowest)

32

isinstance()-used to check if an object is an instance of a specified class or any of its subclasses.
It returns True if the object matches the specified class or type, otherwise it returns False.

Write a program to find str datatype:

data_list = ['abcd','pqrs','xyz',1234, 1.234,True]
for data in data_list:
    if isinstance(data,str):
        print(data)

abcd
pqrs
xyz

Write a program to find str datatype and make them upper:

data_list = ['abcd','pqrs','xyz',1234, 1.234,True]
for data in data_list:
    if isinstance(data,str):
        print(data.upper())

ABCD
PQRS
XYZ

Write a program to find str datatype and make them upper for first two letter:

data_list = ['abcd','pqrs','xyz','a','m',1234, 1.234,True]
for data in data_list:
    if isinstance(data,str):
        if len(data)>= 2:
            print(data.upper()[:2])

AB
PQ
XY

Task:
1) contains n --> names
2) names have 5 letters
3) t --> names end with

names_list = ['sachin','dhoni','rohit','virat']
for name in names_list:
    if 'n' in name:
        print(name,end=" ")
print()
for name in names_list:
    if len(name)==5:
        print(name,end=" ")
print()
for name in names_list:
    if name[-1]=='t':
        print(name,end=" ")

sachin dhoni 
dhoni rohit virat 
rohit virat 

# SaChIn DhOnI rOhIt vIrAt

names_list = ['sachin', 'dhoni', 'rohit', 'virat']

for index, name in enumerate(names_list):
    players = []

    if index < 2:

        for i in range(len(name)):
            if i % 2 == 0:
                players.append(name[i].upper())
            else:
                players.append(name[i].lower())
    else:

        for i in range(len(name)):
            if i % 2 != 0:
                players.append(name[i].upper())
            else:
                players.append(name[i].lower())

    print(''.join(players), end=' ')

SaChIn DhOnI rOhIt vIrAt