CODEWITHSUNDEEP
pythonstacklifo
lisa turner
lisa turner

Reputation: 31

how can I program my code so it displays a stack order from top to bottom in python for a LIFO structure

i've got the code working but I've written my code in python implementing a stack, it is pushing and popping following LIFO but when you view the list it prints it as: 

1 
2 
3

showing the last item which is 3 at the bottom, how can I make it show the last item at the top like a proper stack?

my code is as follows:

stack_pointer = 0
stack =[]
max_length = 2


def view():
        for x in range (len(stack)):
            print(stack[x])
def push():
    global stack_pointer
    if len (stack)> max_length:
        print("Maximum stack length reached!") 
    else:
        stack_pointer = stack_pointer + 1
        item = input("Please enter the  item you wishto add to the stack: ")
        stack.append(item)

def pop():
    global stack_pointer
    if len (stack)<= 0:
        print ("stack is empty!")
    else:
        item = stack.pop
        stack_pointer = stack_pointer - 1
        print ("you just popped out: ", item)

while True:
    print ("")
    print("Python implementation of a stack")
    print("********************************")
    print("1. view Stack")
    print("2. Push onto Stack")
    print("3. Pop out of Stack")
    print("********************************")
    print("")
    menu_choice = int (input("Please enter your menu choice: "))
    print ("")
    print ("")

    if menu_choice == 1:
        view()
    elif menu_choice == 2:
        push()
    elif menu_choice == 3:
        pop()

Upvotes: 0

Views: 122

Answers (2)

SoreDakeNoKoto
SoreDakeNoKoto

Reputation: 1185

This should work: a start of the stack's length - 1 , a stop of -1, and step of -1; no new lists are created or any extra operations, only a modification of the range object parameters, thus it's efficient:

def view():
    for x in range (len(stack) - 1, -1, -1):
        print(stack[x])  # or print(stack[x], end=' ')

Upvotes: 0

dizballanze
dizballanze

Reputation: 1267

Try something like this:

def view():
    print(list(reversed(stack)))

to create reversed copy of your list and print it out.

Upvotes: 1

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