Python Day-23 Lists and list functions,Task

List:
[ ] --> Symbol
-->Collection of Data
-->Collection of Heteregeneous Data(different data types)
-->List is Index Based
-->List is Mutable(Changeable)

Ex: student_data = ['Guru Prasanna', 'B.Com', 23, True, 5.6]
indexing --> 0 1 2 3 4

Example: using while loop and for loop:

student_data = ['Guru Prasanna', 'B.Com', 23, True, 5.6]
i = 0 
while i<len(student_data):
    print(student_data[i],end=' ')
    i+=1
print()

for data in student_data:
    print(data,end=' ')

Output:

Guru Prasanna B.Com 23 True 5.6 
Guru Prasanna B.Com 23 True 5.6

enumerate()-->Useful for index tracking
Enumerate is a built-in function in python that allows you to keep track of the number of iterations (loops) in a loop.

Syntax: enumerate(iterable, start=0)
--> Iterable: any object that supports iteration
--> Start: the index value from which the counter is to be started, by default it is 0

Example:

student_data = ['Guru Prasanna', 'B.Com', 23, True, 5.6]
index = 0
for index,data in enumerate(student_data):
    print(index, data)
    index+=1

Output:

0 Guru Prasanna
1 B.Com
2 23
3 True
4 5.6

To prove list is mutable
Example:

student_data = ['Guru Prasanna', 'B.Com', 23, True, 5.6]

print(student_data)

student_data[1] = 'M.Com'

print(student_data)

Output:

['Guru Prasanna', 'B.Com', 23, True, 5.6]
['Guru Prasanna', 'M.Com', 23, True, 5.6]

List Functions:

1) append()-->Adds an element at the end of the list
2) insert()-->Adds an element at the specified position
3) remove()-->Removes the first item with the specified value(value based removal).
4) pop()-->Removes the element at the specified position(index based removal).

refer- https://www.w3schools.com/python/python_ref_list.asp

Example:

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

print(employee)

employee.insert(2, 'Tamil Nadu')
print(employee)

employee.remove('Madurai')
print(employee)

employee.pop(3)  
print(employee)

Output:

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

del keyword:
The del keyword is used to delete objects.(variables, lists, or parts of a list etc..)
-->Even del can be used to delete particular range.

Example:

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

del l[2:4]

print(l)

Output:

[10, 20, 50, 60]

Difference between del and pop:

del will remove the specified index.(keyword)
pop() removes and returns the element that was removed.(inbuilt method)

calculate total marks and percentage

# Total, 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)

Output:

427
percentage: 85.4

Calculate Highest mark

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

for mark in marks_list:
    if mark>highest:
        highest = mark

print(highest)

Output:

98

Calculate lowest mark

# lowest Mark

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

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

print(lowest)

Output:

65

isinstance(): The isinstance() function returns True if the specified object is of the specified type, otherwise False.
Example:1

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

Output:

abcd
pqrs
xyz

Example:2

#Find str datatype and make them to uppercase
data_list = ['abcd','pqrs','xyz',1234, 1.234,True]
for data in data_list:
    if isinstance(data,str):
        print(data.upper())

Output:

ABCD
PQRS
XYZ

Example:3

#Find str datatype and print only first 2 letters
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])

Output:

AB
PQ
XY

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

names_list = ['sachin','dhoni','rohit','virat']
#1
for name in names_list:
    if len(name)==5:
        print(name,end=' ')
print()

#2
for name in names_list:
    if name[-1] == 't':
        print(name,end=' ')
print()

#3
for name in names_list:
    if 'n' in name:
        print(name,end=' ')   

Output:

dhoni rohit virat 
rohit virat 
sachin dhoni

4) SaChIn DhOnI rOhIt vIrAt-->To get this output

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 == 1:
                players.append(name[i].upper())
            else:
                players.append(name[i].lower())

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

Output:

SaChIn DhOnI rOhIt vIrAt