Problems extending python array declared outside of scope

Question

This is a very basic question, but I can't seem to extend an array with a new item that is added within a function. I haven't gotten push to work either, so I think my array is just not being addressed by the other functions.

The array is declared as a global because otherwise function(s) do not appear to be able to see it. There is probably a much better way, but this is working in a few ways.

this is one set of things I've tried:

        # addTo.insert(0, theItem)
        # weeklytasks.append(theItem)
        # print(addTo) 
        # def askForItem(theItem):
        #     addTo.push(theItem)
        #     print(addTo)
        #

but no luck.

 def initializer():
            print("hello!")
            print("do you want to view the current list, or add a new item?")

setting up some arrays

        global weeklyTasks = ['no items'];
        global monthlyTasks = ['no items']
        global quarterlyTasks = ['no items'];

trying to extend

        quarterlyTasks.extend('the item')
        print(quarterlyTasks);

Neither of these work

        #monthlyTasks.push(0,"task1")
        #monthlyTasks.append("item")

set a var for user's input

        global theItem
        addTo = ""
        theItem = ""


        import string
        print('addTo in globals, ' 'addTo' in globals())

takes an item and checks its timeframe

        def evaluateInput(timeframe):

            global addTo;
            global theItem;
            if timeframe == "Weekly":
                addTo = "weeklyTasks";
                printDestination();
                weeklyTasks.extend(theItem); # why does [].extend not work here?

            if timeframe == "Monthly":
                 addTo = "monthlyTasks"
                 monthlyTasks.insert(0,theItem)
                 printDestination()
            if timeframe == "Quarterly":
                 addTo = "quarterlyTasks"
                 quarterlyTasks.insert(0,theItem)
                 printDestination()

follow up with a request for the timeframe

      def getTimeframe(text): 
        if "add" in text: 
            timeframe = input("Where does this entry go? \n Weekly, Monthly or Quarterly?: ")
            evaluateInput(timeframe) # sends the timeframe to evaluateInput

            # next, ask for the item
            theItem = input('what is the item?')

print a confirmation of what is being added where

        def printDestination():
            print("The item (" + theItem+") will be added to " + addTo)
            # prints where something is going
            print("the "+addTo+" list now contains:") # good, this worked
            print(weeklyTasks) #good, this worked (but the method to push doesn't work)

Are you defining your globals within the initializer function? It's a bit hard to tell. If so, remember you need to call the initializer function before the globals will be available. (I would recommend fixing the indentation in your examples - it's a bit hard to tell what code is in what block.) — Andrew Guy
– Andrew Guy, Commented Sep 3, 2016 at 5:13

VPfB · Accepted Answer · 2016-09-03 07:45:05Z

3

A working example of all mentioned functions. global is not required, because the tasklist is not re-assigned in the function, only its methods are called.

tasklist = ['one']

def testfunc():
    # no global required
    tasklist.append('two')
    tasklist.extend(['three', 'four'])
    tasklist.insert(0, 'zero')

testfunc()
print(tasklist)
# ['zero', 'one', 'two', 'three', 'four']

Hope it helps.

answered Sep 3, 2016 at 7:45

VPfB

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Magnificent Kira · Accepted Answer · 2016-09-03 08:22:58Z

1

Here's the working solution in python 3.2 to add items to list in function:

weeklyTasks = ['No work Sunday']
def AddWeeklyTask():
    weeklyTasks.extend(['Work On'])
    weeklyTasks.append('Do not work on weekends')
    weeklyTasks.insert(2,'Friday')

print(weeklyTasks)
AddWeeklyTask()
print(weeklyTasks)

Output:

['No work Sunday']
['No work Sunday', 'Work On', 'Friday', 'Do not work on weekends']

There is no need to declare list as global

answered Sep 3, 2016 at 8:22

Magnificent Kira

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