在 python 中的两个函数之间共享数据

Question

so i have a code which loops until the user types cancel and allows the user to input things into a list and then see the list if they want to. but i have a problem wherein if i want to see the list the user has to input again and the data i typed when i added to the list is gone. here is the code pls help me im pretty new to python.

answer=""
def addlist():
     list=input("what would you like to add? ")
     print("added successfully")
     return list
def showlist():
     list=addlist()
     print(list)
while answer !="cancel":
     answer=input("what would you like to do?, 1 for add to list, 2 for show list, cancel to close")
if answer=="1":
     addlist()
elif answer=="2":
     showlist()
else:
     print("wrong value")

Answer 1

So we've got a few problems here:

1. addlist doesn't actually create a list, it creates a string.
2. showlist depends on addlist, when really we should be looking for a common list that we toss everything into (assuming you actually want to work with a list)
3. Your indentation in your while loop is incorrect

def addlist():
    item = input("what would you like to add?")
    return item


def showlist(mylist):
    print(mylist)

mylist = []
answer = ""
while answer != "cancel":
    answer = input("what would you like to do?, 1 for add to list, 2 for show list, cancel to close")
    if answer == "1":
        add_item = addlist()
        mylist.append(add_item)
        print("added successfully")
    elif answer == "2":
        showlist(mylist)
    else:
        print("wrong value")

That above seems to do the trick.

You seem to have a grasp on return statements, so how about you pass each of those functions a common list as I did mylist and have them do stuff with that.

I changed addlist to actually just get the item we want to add to the list and then return that item and append it outside of the function. In showlist I pass mylist to it via: showlist(mylist) and then print the list I get in that function.

Answer 2

You should create a list element in order to append your items in it. You can see more here . One way to do what you want is like this:

answer = ""
temp_list = []

def addlist():
    item = input("what would you like to add? ")
    temp_list.append(item)

    print("added successfully")

def showlist():
    print(temp_list)


while answer != "cancel":
    answer = input(
        "what would you like to do?, 1 for add to list, 2 for show list, cancel to close")
    if answer == "1":
        addlist()
    elif answer == "2":
        showlist()
    else:
        print("wrong value")