如何使用函数的返回值并在下一个函数中使用它

Question

I want to use the first function's value to apply on the second function that I am defining.

I defined collectUserInputTime() which takes no argument.

Once I called collectUserInputTime() , it does not change the value of startHour and startMinute .

Also, if I don't define startHour and startMinute outside of functions, I will get a startHour and startMinute undefine.

I also tried to add print( startHour )inside of collectUserInputTime() , it did print out my input(), but it does not change the startHour outside of the function. startHour still remain as an empty string.

startHour = ''
startMinute = ''
def collectUserInputTime():
     print('Enter the time the call starts in 24-hour rotation:')
     data = input()
     astop = data.find(':')
     startHour = data[0:astop]
     startMinute = data[astop+1:]
     return startHour and startMinute



def validateUserInputTime(startHour , startMinute):
    if (startHour in hoursList and startMinute in minutesList):
        print('it is valid')
    else:
        print('input invalid')

collectUserInputTime()
validateUserInputTime(startHour, startMinute)

How am I able to use the return value from collectUserInputTime() which are startHour and startMinute ? Eventually, I can validate in my function validateUserInputTime(startHour, startMinute)

Answer 1

startHour = ''
startMinute = ''
def collectUserInputTime():
     print('Enter the time the call starts in 24-hour rotation:')
     data = input()
     astop = data.find(':')
     startHour = data[0:astop]
     startMinute = data[astop+1:]
     print(startHour)
     print(startMinute)
     return startHour, startMinute

ret_val = collectUserInputTime()
print("Hours: ", ret_val[0])
print("Minutes: ", ret_val[1])

OUTPUT:

13:54
13
54
Hours:  13
Minutes:  54

and so you can use it in your validateUserInputTime(startHour , startMinute) :

def validateUserInputTime(startHour , startMinute):
    if (startHour in hoursList and startMinute in minutesList):
        print('it is valid')
    else:
        print('input invalid')

ret_val = collectUserInputTime()
startHour = ret_val[0]
startMinute = ret_val[1]
validateUserInputTime(startHour, startMinute)

Answer 2

startHour = ''
startMinute = ''
def collectUserInputTime():
     print('Enter the time the call starts in 24-hour rotation:')
     data = input()
     astop = data.find(':')
     startHour = data[0:astop]
     startMinute = data[astop+1:]
     return (startHour, startMinute)



def validateUserInputTime(startHour , startMinute):
    if (startHour in hoursList and startMinute in minutesList):
        print('it is valid')
    else:
        print('input invalid')

rtn_data = collectUserInputTime()
validateUserInputTime(rtn_data[0], rtn_data[1])

Answer 3

First of all I would change what the function collectUserInputTime() returns. I would use a list!

Then I would use a CS concept called "Helper function": in short, you can call a function within another function.

The code is the following

def collectUserInputTime():
 data = input('Enter the time the call starts in 24-hour rotation: ')
 astop = data.find(':')
 startHour = data[0:astop]
 startMinute = data[astop+1:]
 return [startHour, startMinute]

def validateUserInputTime():
 hour = collectUserInputTime()
 startHour, startMinute = int(hour[0]), int(hour[1]) # if lists are int_lists
 if (startHour in hoursList) and (startMinute in minutesList):
     print('It is valid')
 else:
     print('Input invalid')

I have also made the code more "Pythonic" in few lines!

Hope this helps