Question

In Python, How to return a copy of the list, return the max value in the list, flatten the list of lists to have only one level, e.g. >>> flatten([[1, 2], [3, 4], [5, 6]]) >>> [1, 2, 3, 4, 5, 6]

I want to solve the problem without a list comprehension and with a list comprehension to see the difference with comments to be able to understand it

Answer 1

#list comprehension can only be used in flattening the list. There is no need to use it in
#finding maximum in list and creating the copy of list

#function which will flatten the list of list without a list comprehension
def flat(l):
#declare an empty list output
output=[]
#outer loop run over the list l passed
for i in l:
#inner loop run over each element of l in each iteration
for j in i:
#append the individual element into the output list
output.append(j)
#print the output flattened list
print("Flattened list without using list comprehension: ",output)

#function which will flatten the list by using list comprehension
def flat1(l1):
#declare an empty list output1
output1=[]
#list comprehension is basically reducing the space taken by the code
#which will generate same result as the previous code
#Now here nested loops are same as previous one except that it is written in same line
#loop will run and j is the individual element which will be appended one by one in output1
#list in each iteration
output1=[j for i in l1 for j in i ]
#printing the list output1
print("Flattened list by using list comprehension: ",output1)

#function which will return the copy of the list passed
#this copy will be shallow copy so that changing the copy of list
#does not change the original list l
def copy_list(l):
#using copy() method to create shallow copy of list l
return l.copy()
#function which will return the maximum number from the list
def max_list(l):
#setting m variable to first element of list
m=l[0]
#iterating over the list l
for i in l:
#if the element coming in iteration > the first element that is m then
#m is changed to that iterated element
if(i>m):
m=i
#Atlast m will be the maximum element so it will be returned
return m
#defining a listof lists l
l=[[1,2],[3,4],[5,6]]
#passing it to flat function
flat(l)
#passing it to flat1 function
flat1(l)
#defining another list l1
l1=[34,82,51,67]
#calling function which will return the copy of the list passed and storing it in l2
l2=copy_list(l1)
#printing l2
print("Copy of list: ",l2)
#using l2 copy of l1 to find maximum in it by calling the function max_list
#and passing l2 to it
#max number returned gets printed
print("Maximum element of list: ",max_list(l2))
  

#list comprehension can only be used in flattening the list. There is no need to use it in #finding maximum in list and creating the copy of list #function which will flatten the list of list without a list comprehension def flat(1): #declare an empty list output output=[] #outer loop run over the list i passed for i in 1: #inner loop run over each element of 1 in each iteration for j in i: #append the individual element into the output list output.append()) #print the output flattened list print("Flattened list without using list comprehension: ", output) #function which will flatten the list by using list comprehension def flati (11): #declare an empty list outputi outputl=[] #list comprehension is basically reducing the space taken by the code #which will generate same result as the previous code #Now here nested loops are same as previous one except that it is written in same line #loop will run and ) is the individual element which will be appended one by one in outputi #list in each iteration output1=[] for i in 11 for j in il #printing the list outputi print ("Flattened list by using list comprehension: ", outputi) #function which will return the copy of the list passed #this copy will be shallow copy so that changing the copy of list #does not change the original list i def copy list (1): #using copy() method to create shallow copy of list i return 1. copy () #function which will return the maximum number from the list def max list (1): #setting m variable to first element of list m=1[0] #iterating over the list i

#iterating over the list i for i in 1: #if the element coming in iteration > the first element that is m then #m is changed to that iterated element if (im) : m=i #Atlast m will be the maximum element so it will be returned return m #defining a listof lists i 1=([1,2], [3,4], [5,6]] #passing it to flat function flat (1) #passing it to flati function flati (1) #defining another list 11 11=[34,82,51,67] #calling function which will return the copy of the list passed and storing it in 12 12=copy list (11) #printing 12 print ("Copy of list: ",12) #using 12 copy of 11 to find maximum in it by calling the function max_list #and passing 12 to it #max number returned gets printed print ("Maximum element of list: ", max_list (12))

6] Flattened list without using list comprehension: (1, 2, 3, 4, 5, Flattened list by using list comprehension: (1, 2, 3, 4, 5, 6] Copy of list: [34, 82, 51, 671 Maximum element of list: 82