为什么我的Validation（）函数没有运行？

Question

This is the code I have written to try and display a message of whether or not somebody is able to vote, after taking in age and the type of election, but after I enter the type of election it stops. Can anyone help? Here is my code:

def Validation():
if election == 'EU' or election == 'UK':
    if age < 110 and age > 18:
        print('You are eligable to vote in this election')
    else:
        print('You are not eligable to vote in this election')

    if election is 'Scottish' or election is'local':
        if age < 110 and age > 16:
            print('You are eligable to vote in this election')
        else:
            print('You are not eligable to vote in this election')

Answer 1

Put == instead of is . Also be aware that == should match every character in order to be true (It's somewhat oubvious, but just remebering you that), so if you have a selection named " L ocal" and you're trying to compare with " l ocal", it's not the same.

Your code should look like this:

def Validation():
    if election == 'EU' or election == 'UK':
        if age < 110 and age > 18:
            print('You are eligable to vote in this election')
        else:
            print('You are not eligable to vote in this election')

        if election == 'Scottish' or election == 'local':
            if age < 110 and age > 16:
                print('You are eligable to vote in this election')
            else:
                print('You are not eligable to vote in this election')

Answer 2

In addition to what @Fusseldieb writes, think about separating the configuration from the validation function.

The rules can be expressed like this:

rules = {
    'UK': {'min-age': 18, 'max-age': 110},
    'EU': {'min-age': 18, 'max-age': 110},
    'Scottish': {'min-age': 16, 'max-age': 110},
    'local': {'min-age': 16, 'max-age': 110},
}

With that out of the way, the validation function becomes shorter and, in contrast to your current approach, it does not need any changes if the set of rules gets bigger.

def Validation(election):
    if election in rules:
        rule = rules[election]
        if age >= rule['min-age'] and age <= rule['max-age']:
            print('You are eligible to vote in this election')
        else:
            print('You are not eligible to vote in this election')
    else:
        print('No rules configured for this country')

Answer 3

Disclaimer: The following isn't what I usually do, or what usually happens on this site. It exceeds the question scope by far and pretty much comes down to a 101 or a tutorial.

---

Your code has multiple problems and none of them can easily be fixed by spotting the mistake and pointing you to it. The entire approach to the problem needs to be re-worked from scratch. You try to do to many things at once, which always results in code that has interlocked issues.

Let's break down what you try to do.

1. ask the user for his age, which must be an integer between 0 and 110.
2. ask them for their region, which must be one of a limited set of choices
3. inform them whether their age allows them to vote in their region

Even more basically, you want to do this:

1. ask the user for a value
2. make sure the value fulfills a certain criterion (like "is a number" or "is a number between x and y" )
3. repeat until the user has entered a compliant value

These steps could be expressed in pseudo code:

def input_value():
    while True:
        value = input('Please enter a value: ')
        if value == 'valid':
            return value

So we have an endless loop that keeps asking the user for a value and only when the value is okay we return it.

---

To ask for an integer, the function could look like this:

def input_int():
    while True:
        value = input('Please enter a number: ')
        if value.isdigit():
            return int(value)

To ask for an integer that falls into a certain range, like an age value, we can utilize the same pattern and use the input_int() function:

def input_int_in_range(min, max):
    while True:
        value = input_int()
        if value >= min and value <= max:
            return value
        else:
            print('Please input values between %i and %i.' % (min, max))

Notice how the else: branch informs the user about the valid range after the first wrong entry.

Now assuming that we have a dict of voting rules, like indicated in my other answer:

regions = {
    'UK': {'min-age': 18, 'max-age': 110},
    'EU': {'min-age': 18, 'max-age': 110},
    'Scottish': {'min-age': 16, 'max-age': 110},
    'Local': {'min-age': 16, 'max-age': 110},
}

we could write another function that lets the user pick one of those by key. The function nicely follows the established pattern:

def input_choose(dict):
    while True:
        value = input('Please input your choice: ')
        if value in dict:
            return dict[value]
        else:
            print('Valid choices are: %s'  % ', '.join(dict.keys()))

---

Now we have all the basic parts in place and can put them together:

# main program
while True:
    print("\nPlease enter your age.")
    age = input_int_in_range(0, 110)

    print("\nPlease enter the election you are voting for.")
    rule = input_choose(rules)

    if age >= rule['min-age'] and age <= rule['max-age']:
        print("\nYou are eligible to vote in this election.\n")
    else:
        print("\nYou are not eligible to vote in this election.\n")

As an exercise you can create a validation function, but the way this has been designed every input step is self-validating, so that a final validation step is not really necessary.