Question

I have two similar functions function def A() and function def B() written so far, and it works, but I would like to do it, so that after a user finishes writing data in function B(),… he is given an option to either quit, or begin the process again with writing data in function A()

So that theoretically, user could repeat the process a million times before he (for example) hits ENTER to quit the program.

How would I achieve that?

def A(parameters):
    content...
    ...
    ...

def B(parameters):
    content...
    ...
    ...

Press R to repeat with def A (parameters), press Q to quit:

Answer 1

It’s probably better to merge the functionality of A() with B() and pass a flag, however here is a solution that allows A() to be called after B() until the user hits RETURN:

def A():
    print 'Processing in A!'

def B():

    choice = ''
    print 'Processing in B!'

    while choice.lower().strip() != 'r':    
        choice = raw_input("Press R to repeat, RETURN to exit: ").lower().strip()            
        if choice == '':
            return False
        if choice  == 'r':
            return True

while B():
    A()

Output:

Processing in B!
Press R to repeat, RETURN to exit: R
Processing in A!
Processing in B!
Press R to repeat, RETURN to exit: r
Processing in A!
Processing in B!
Press R to repeat, RETURN to exit: notR
Press R to repeat, RETURN to exit: 

Some notes:

lower() returns whatever the user types as all lowercase characters allowing r and R to be treated the same.

strip() removes any leading or trailing whitespace from the input.