Day-26 List Comprehension

List Comprehension:

It's a syntactically elegant method to create or manipulate lists in a single line of code.

Write a program to print the fruits contains letter 'a'(using for loop):

fruits = ["apple", "banana", "cherry", "kiwi", "mango"]
newlist = []

for x in fruits:
  if "a" in x:
    newlist.append(x)

print(newlist)

['apple', 'banana', 'mango']

(Using list comprehension):

fruits = ["apple", "banana", "cherry", "kiwi", "mango"]

newlist = [x for x in fruits if "a" in x]
print(newlist)

['apple', 'banana', 'mango']

Write a program to find the square root of given number:

l = [10,20,30,40]
newlist = []

#using for loop
for num in l:
    newlist.append(num**2)
print(newlist)

#using loop in comprehensive way
newlist = [num**2 for num in l]
print(newlist)

[100, 400, 900, 1600]
[100, 400, 900, 1600]

Find similar numbers from 2 lists and different numbers from the same 2 lists:

l1 = [10,20,30,40]
l2 = [30,40,50,60]

#for loop
for num in l1:
    for no in l2:
        if num== no:
            print(num,end=' ')
#comprehensive
print([num for num in l1 for no in l2 if num==no])

30 40 
[30, 40]

1 = [10,20,30,40]
l2 = [30,40,50,60]

#comprehensive
output = [num for num in l1 if num not in l2]

output = output + [num for num in l2 if num not in l1]
print(output)

#for loop
for num in l1:
    if num not in l2:
        print(num,end=' ')

for num in l2:
    if num not in l1:
        print(num,end=' ')

[10, 20, 50, 60]
10 20 50 60

Write a program for the given output in comprehensive approach:

l1 = [1,2,3]
l2 = [5,6,7]
Output:[(1, 5), (1, 6), (1, 7), (2, 5), (2, 6), (2, 7), (3, 5), (3, 6), (3, 7)]

l1 = [1,2,3]
l2 = [5,6,7]

l = [(i,j) for i in l1 for j in l2 if i!=j]
print(l)

[(1, 5), (1, 6), (1, 7), (2, 5), (2, 6), (2, 7), (3, 5), (3, 6), (3, 7)]

Write a program for the given output:
s = "a1b2c3"
output: abc123

Method:1

s= "a1b2c3"

alpha_list = []
num_list = []

for letter in s:
    if letter.isalpha():
        alpha_list.append(letter)
    else:
        num_list.append(letter)

print("".join(alpha_list+num_list))

Method:2

s = "a1b2c3"
letter=''.join([i for i in s if i.isalpha()])
no=''.join([i for i in s if i.isdigit()])

print(letter+no)

abc123

Write a program for the given output:

s = "a4k3b2"
output: aeknbd

s = "a4k3b2"
i = 0 
while i<len(s):
    first = s[i]
    second = int(s[i+1])
    print(first, chr(ord(first)+second),sep='',end='')
    i+=2

aeknbd

Task:

1) Write a program to get the output 'abbbbklllbcc'

s = "a4k3b2"
i = 0

while i < len(s):
    first = s[i]  
    second =int(s[i + 1]) 
    print(first,chr(ord(first)+1)*second,sep='',end='')
    i+=2

abbbbklllbcc

2) Write a program to get the output 'aaaaakkkkbbb'

s = "a4k3b2"
i = 0

while i < len(s):
    first = s[i]  
    second =int(s[i + 1]) 
    print(first,chr(ord(first))*second,sep='',end='')
    i+=2

aaaaakkkkbbb

3.Join the given matrix into single list using comprehensive for and normal for loop.

Method:1(Using for loop)

matrix = [[10,20,30], [40,50,60], [70,80,90]]
output=[]

for i in matrix:
    for j in i:
        output.append(j)
print(output)

Method:2(Using comprehensive for loop)

matrix = [[10, 20, 30], [40, 50, 60], [70, 80, 90]]

output = [j for i in matrix for j in i]
print(output)

[10, 20, 30, 40, 50, 60, 70, 80, 90]

4.l = ['ABC','DEF', 'GHI', 'JKL']
Get OUTPUT: ['ABC', 'def','GHI', 'jkl']

l = ['ABC', 'DEF', 'GHI', 'JKL']

output = [] 
for i, alpha in enumerate(l):
    if i % 2 != 0:
        output.append(alpha.casefold())
    else:
        output.append(alpha)
print(output)

['ABC', 'def', 'GHI', 'jkl']

5.Find the row wise total for the given matrix:

matrix = [[10,20,30], 
          [40,50,60], 
          [70,80,90]]
for inner in matrix:
    total = 0
    for index,num in enumerate(inner):
        total+=num
    print(total,end=' ')

60 150 240