This example is just a basic program - I'm a new Coder - learning and experimenting whilst messing about .. Currently testing on Python 3.6 IDE and PyCharm - apologies for double spacing code - but looks a mess without.
Looking for guidance for returning a value from a function.
Have tried dozens of different methods / searched the forum, but closest answer this layman could understand stated I needed to use the return value otherwise it will be forgotten .. So added print(age_verification, " example test value .. ") at various locations - but nothing gets returned outside the function ..
Have tried returning Boolean / integer / string values and adapting - nothing with each variant .. Added a default age_verification = False variable before the function // or // referenced within function for 1st time .. Doesn't effect the return value except IDE doesn't state "unresolved reference"
Tried a line-by-line python visualizer - but again - age_verification value disappears instantly after exiting the function . :-(
==================================================================
Using 1 Single Function
def age_veri(age, age_verification) :
if age < 18 :
age_verification = False
print(age_verification, " is false .. Printed to test variable ..")
return age_verification
elif age >= 18:
age_verification = True
print(age_verification, " is True.. Printed to test variable ..")
return age_verification
return age_verification # ( -- have tested with/without this single-indent line & with/without previous double-indent return age_verification line.)
age=int(input("Enter Your Age : ")
age_verification = False # ( -- have tried with / without this default value)
age_veri(age, False)
if age_verification is False:
print("You failed Verification - Age is Below 18 .. ")
elif age_verification is True:
print("Enter Website - Over 18yrs")
else:
print(" Account not Verified .. ")
==================================================================
Same Example - Using 2 Functions
def age_variable(age):
if age < 18:
age_verification = False
print (age_verification, " printing here to use value and help test function..")
return age_verification
elif age >= 18:
age_verification = True
print (age verification, " printing here to use value and help test function..")
return age_verification
return age_verification (tried with and without this line - single indent - same level as if / elif)
def are_verified(age_verification):
if age_verification is False:
print("Age Verification Failed .. ")
elif age_verification is True:
print("Visit Website .. ")
else:
print("Verification Incomplete .. ")
age = int(input("Enter Your Age : ")
age_variable(age)
are_verified(age_verification)
==============================================================
Any advice is appreciated - wasted most of today hitting my head against the wall .. And apologies in advance .. Know it'll be something really basic - but appear to be using same formatting as others :-)
THANK YOU
print doesn't return values, it will just display the value to stdout or the console. If you want to return a value with conditions, understanding scope is helpful. Your comment regarding returning variables otherwise they will be "forgotten" is correct. Variables defined and not returned by the function will go away when the function executes:
def my_func(var1):
var2 = var1
var3 = 5
return var3
print(my_func(1), var2)
The print statement will throw a NameError because var2 isn't defined outside of the function, nor is it returned. For your example, you'd want something like this:
def age_verify(age):
if age < 18:
print("Failed Verification")
return False
else:
print("Verification Complete")
return True
# Call and assign to var
age = int(input("Enter Your Age : ")
age_verification = age_verify(age)
This way you are saving the returned value as the variable age_verification
EDIT:
To further expand on the scope concept, using the same definition for my_func:
def my_func(var1):
var2 = var1
var3 = 5
return var3
We assign the returned var3 to a variable like so:
myvar = my_func(5)
As noted, the name var3 isn't actually returned, just the value. If I were to run
myvar = my_func(5)
print(var3)
I would get a NameError. The way to get around that would be to do:
var3 = my_func(5)
because now var3 is defined in global scope. Otherwise, I would have to edit my function to make var3 global:
def my_func(var1):
global var3
var2 = var1
var3 = 5
# The return statement is then a bit redundant
my_func(5)
print(var3)
# prints 5 in global scope
Hopefully this is a bit clearer than my original answer