Postfix Evaluation of an expression using Python 3

postfix_evaluation_of_an_expression_using_Python3.py

s = []

while True:
	'''Taking Input until user clicks a blank enter'''
	item=input("Enter your postfix expression character by character or press enter to exit ")
	if (item==''):
		break
	s.append(item) #Adding items to stack one by one

print(s) #your entered expression

j=[]

for i in range(len(s)): #loop for checking each characer one by one
    if(s[i].isdigit()==True): #if the character is a digit that will be stored in another array j
        j.append(int(s[i]))
    elif(s[i]=='*'): 
#if * operator then first pop will pop the last element and second pop will do the last-1 element. 
#now we need to swap as the left most between the two will be operand 1, and operand2 will be the right one.
    	x=j.pop()
    	y=j.pop()
    	res = y * x
    	j.append(res)
    elif(s[i]=='+'):
    	x=j.pop()
    	y=j.pop()
    	res = y + x
    	j.append(res)
    elif(s[i]=='-'):
#if * operator then first pop will pop the last element and second pop will do the last-1 element. 
#now we need to swap as the left most between the two will be operand 1, and operand2 will be the right one.
#ex: if 6,4 is appended and we do operation withour swapping it'll be 4-6=-2
    	x=j.pop()
    	y=j.pop()
    	res = y - x
    	j.append(res)
    elif(s[i]=='/'):
#ex: if we do not swap 6,3 will be resulted as 3/6.
    	x=j.pop()
    	y=j.pop()
    	res=y/x
    	j.append(res)


print('Your postfix expression result is',j[0])

Tq.its helpful