无法使用另一个函数/ python文件中的返回值

Question

I am new to python-ish and trying to user the value held in the server variable that is returned at the bottom of select_target_server_type in another program. The first set of code is my menu.py and its just an input/decision tree.

My second code is rest_engine.py which calls menu.start_program() and that works great but when I want to retrieve the value of a function in one of the menu functions I cant get it to work it seems.

def start_program():
    select_target_server_type()


def select_target_server_type():
    # SUPPORTED SERVERS FOR API CALLS
    # DISPLAYS A LIST TO USER TO CHOOSE FROM

    print("\nWelcome!\nThese are the supported systems, please select a value by entering the corresponding "
          "numbered value\n")

    while True:
        try:
            print("1. APIC-EM")
            print("2. ISE")
            print("3. CSR")
            print("4. Quit")
            server = int(input("\nPlease select a SYSTEM TYPE to continue:   "))

            if 0 >= server or server >= 5:
                print("\n***Incorrect Selection***\n\n")
                pass
            else:
                break

        except Exception as e:
            print("\n\n***oops***")
            sys.exit(1)

    while True:
        try:
            if server == 1:
                print("\nYou have selected APIC-EM \n")
                api_top_menu()
            elif server == 2:
                print("\nYou have selected ISE \n")
                api_top_menu()
            elif server == 3:
                print("\nYou have selected CSR \n")
                api_top_menu()
            elif server == 4:
                print("\nQUITTING APPLICATION\n")
                sys.exit(0)
        except Exception as e:
            print("\n\n***oops***")
            sys.exit(1)
        return server

Second program rest_engine.py (calls the first)

#!/usr/bin/python3

import json
import requests
import menu


menu.start_program()

name = menu.select_target_server_type()
print(name)

Functioning Code Output:

> /usr/bin/python3.5 /home/danield/PycharmProjects/YODA/rest_engine.py
> 
> Welcome! These are the supported systems, please select a value by
> entering the corresponding numbered value
> 
> 1. APIC-EM
> 2. ISE
> 3. CSR
> 4. Quit
> 
> Please select a SYSTEM TYPE to continue:   1
> 
> You have selected APIC-EM 
> 
> 1. GET
> 2. PUT
> 3. DELETE
> 4. quit Please select a function to continue:   1
> 
> You chose to use GET
> 
> 1. INVENTORY
> 2. NETWORK DISCOVERY
> 3. TBD
> 4. Quit Please select the FUNCTION category:   1
> 
> You chose Inventory
> 
> 
> 
> ***oops***
> 
> Process finished with exit code 1

Answer 1

I think this is your problem:

Post all your code! We cannot see the code that displays the other lists (ie the function and FUNCTION) lists. How can we help with a partial problem? Update your post!

menu.start_program() is called, and in menu.py it calls select_target_server_type() within it. However, select_target_server_type() is set to return server , so it will return sever to the calling function start_program() . However, the start_program() function isn't coded to receive a return from its function call to select_target_server_type() . However, before it can even return server an error is being caught somewhere. But we cant see api_top_menu() so we can't help you there unless you update your post.

Try these changes:

rest_engine.py

#!/usr/bin/python3

import json
import requests
import menu

name = menu.start_program()

print (name)

menu.py

def start_program():
    server = select_target_server_type()


def select_target_server_type():
    # SUPPORTED SERVERS FOR API CALLS
    # DISPLAYS A LIST TO USER TO CHOOSE FROM

    print("\nWelcome!\nThese are the supported systems, please select a value by entering the corresponding "
          "numbered value\n")

    while True:
        try:
            print("1. APIC-EM")
            print("2. ISE")
            print("3. CSR")
            print("4. Quit")
            server = int(input("\nPlease select a SYSTEM TYPE to continue:   "))

            if 0 >= server or server >= 5:
                print("\n***Incorrect Selection***\n\n")
                pass
            else:
                break

        except Exception as e:
            print("\n\n***oops***")
            sys.exit(1)

    while True:
        try:
            if server == 1:
                print("\nYou have selected APIC-EM \n")
                api_top_menu() # we need to see this code too!
            elif server == 2:
                print("\nYou have selected ISE \n")
                api_top_menu()
            elif server == 3:
                print("\nYou have selected CSR \n")
                api_top_menu()
            elif server == 4:
                print("\nQUITTING APPLICATION\n")
                sys.exit(0)
            return server # will end the infinite try here
        except Exception as e:
            print("\n\n***oops***")
            sys.exit(1)

Answer 2

A few things. First, seems like not all of those things need to be in while loops, but that's a separate issue. Second, when you do menu.start_program(), you're running your function select_target_server_type, but you don't store the return value. You only try to store the return value when you call the whole thing again: name = menu.select_target_server_type()

But you never get to that line (with name=...), because the first call, to start_program, terminates the running process.

Third, your program is running into an error and thus terminating via the sys.exit(1) line, so the function never gets the chance to return anything.