Why my code running None.

Question

def sq(x):
for i in x:
a=(i*i)
z=[]
print(z.append(a))

a=[1,2,3,4]
sq(a)

output=None
None
None
None

Answer 1

your loop contains z=[] which means each time the loop runs it is clearing the list. also, your trying to print a function that has no value. it is a function to add something to a list. if you want to print each letter being added, just print a. if you want to print the growing list, just print z

try this

Why my code running None.

def sq(x):
z=[]
for i in x:
a=(i*i)
z.append(a)
print(a)

a=[1,2,3,4]
sq(a)

Answer 2

#Try list comprehension
[print(i*i) for i in range(1,5)]