[Tutor] menu based programs

[Alan Gauld]

On 16/01/15 23:39, Siya 360 wrote:
> i want to learn how to write code to interact with the user,
 > in a sequence where
 > if option 1, then display a,
 > if 2 then display b,
 > if 3 display c,
 > if 4 display exit,

> if 1 selected, leads to option a, which in turn has it own options


You don't say how these menus are presented.
One option is the cmd module which has a lot of built in features such 
as context sensitive help screens. But it is similar in style ton the 
Python help() command which may not be what you want.

Simple text based menus are just built using print statements
(triple quoted multi-line strings often help a lot)

Here is a very simple example modelled on your description

#####################
def readMenu(menu):
     while not (1<= choice <= len(menu) ):
        for index, item in enumerate(menu,start=1):
            print (index, item)
        choice = input("\nchoose an item: ")
     return choice-1

def display(choice):
     print( 'ABC'[choice] )

menu = ['display A','display B', display C', 'exit']

while True:
    choice = readMenu(menu)
    if choice == 3:
       break
    else: display(choice)
########################


You can use a table driven approach with a data structure to link menu 
choices to screens. But without knowing what you want the application to 
look like it's hard to give solid advise

And if you want a GUI then it's a whole new ball game...

hth
-- 
Alan G
Author of the Learn to Program web site
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