python3 TypeError: 'function' object is not iterable

Question

What change is required in the source code?

    def Update():
        print('\n')
        print("Update")
        cmd = os.system('xterm -e apt-get update')
        print("Finish update")

    def AptUpdate():
        print('\n')
        print("Update system? {Y/N}")
        print("Y or y")
        print("N or n")
        code = input("Command > ")
        if code == 'y' or code == 'Y':
            for i in Update():
                return Update
            elif code == 'n' or code == 'N': 
                return 
            else: 
                print("Warning!")

    AptUpdate()

    exception:

    Traceback (most recent call last):
      File "pybash.py", line 110, in 
        AptUpdate()
      File "pybash.py", line 102, in AptUpdate
        for i in Update:
    TypeError: 'function' object is not iterable

Solution

What the traceback error is pointing out is the misuse of for statement:

for i in Updt():

for in python 3 is as follows: "Python’s for statement iterates over the items of any sequence (a list or a string), in the order that they appear in the sequence." (source: python 3.3 documentation, section 4: More control structures Python 3

Since a function is neither a list nor a string, you can't use the format:

for [variable] in [function]():

As far as what needs to be fixed, it depends on what those two functions are supposed to accomplish individually.

Comments

[Martijn Pieters]

Your traceback and actual code do not match. The answer lies in the exact difference between the two.

[Martijn Pieters]

Your next error will be 'NoneType' object is not iterable, as Updt doesn't actually return anything useful.

[jfs]

you should probably read Difference between returns and printing in python? and Python: What is the Formal Difference Between Print and Return?

[ElMaestroDeToMare]

You don't return anything. You should return an iterable object such an array or a list, etc

[Rushy Panchal]

If the function returns an iterable-type, then this can be used. His issue is that in his actual code (based on the error), he never calls the function, but attempts to iterative over a reference of the function itself.

[user3460822]

That is true, I suppose the purpose of the block given is confusing to me because I don't do a whole lot of shell scripts.

[Yvonne Aburrow]

I forgot to put the () on the end of my function call, so Python threw the same error. routes = db.get_all_routes (new line) for route in routes: should be routes = db.get_all_routes() (new line) for route in routes: