Python: How to print menu numbered vertically-CodePudding

The final code will print the distance between airports. I'm trying to print the menu with the names of the airports numbered and vertically. I really struggle to find my mistakes.

This code doesn't raise any error, it just prints nothing, empty.

airport_data = """
Alexandroupoli  40.855869°N 25.956264°E
Athens 37.936389°N 23.947222°E
Chania  35.531667°N 24.149722°E
Chios   38.343056°N 26.140556°E
Corfu 39.601944°N 19.911667°E"""

airports = []

import re
airport_data1 = re.sub("[°N@°E]", "", airport_data)

def process_airports(string):
    airports_temp = string.split()
    airports = [(airports_temp[x], float(airports_temp[x   1]), float(airports_temp[x   2])) for x in
                range(0, len(airports_temp), 3)]
    return airports

def menu():
    for airport_data in range(airport_data1):
        print(f'{airport_data   1} {name[number]}')

CodePudding user response：

My first guess is, your code does not print anything without errors because you never actually execute process_airports() nor menu().

You have to call them like this at the end of your script:

something = process_airports(airport_data1)
menu()

This will now raise some errors though. So let's address them. The menu() function will raise an error because neither name nor number are defined and because you are trying to apply the range function over a string (airport_data1) instead of an integer.

First fixing the range error: you mixed two ideas in your for-loop: iterating over the elements in your list airport_data1 and iterating over the indexes of the elements in the list.

You have to choose one (we'll see later that you can do both at once), in this example, I choose to iterate over the indexes of the list.

Then, since neither name nor number exists anywhere they will raise an error. You always need to declare variables somewhere, however, in this case they are not needed at all so let's just remove them:

def menu(data):
    for i in range(len(data)):
        print(f'{i   1} {data[i]}')

processed_airports = process_airports(airport_data1)
menu(processed_airports)

Considering data is the output of process_airports()

Now for some general advices and improvements.

First, global variables. Notice how you can access airport_data1 within the menu() function just fine, while it works this is not something recommended, it's usually better to explicitly pass variables as arguments.

Notice how in the function I proposed above, every single variable is declared in the function itself, there is no information coming from a higher scope. Again, this is not mandatory but makes the code way easier to work with and understand.

airport_data = """
Alexandroupoli  40.855869°N 25.956264°E
Athens 37.936389°N 23.947222°E
Chania  35.531667°N 24.149722°E
Chios   38.343056°N 26.140556°E
Corfu 39.601944°N 19.911667°E"""

airports = []

import re
airport_data1 = re.sub("[°N@°E]", "", airport_data)

def process_airports(string):
    airports_temp = string.split()
    airports = [(airports_temp[x], float(airports_temp[x   1]), float(airports_temp[x   2])) for x in
                range(0, len(airports_temp), 3)]
    return airports

def menu(data):
    for i in range(len(data)):
        print(f'{i   1} {data[i]}')

# I'm adding the call to the functions for clarity
data = process_airports(airport_data1)
menu(data)

The printed menu now looks like that:

1 ('Alexandroupoli', 40.855869, 25.956264)
2 ('Athens', 37.936389, 23.947222)
3 ('Chania', 35.531667, 24.149722)
4 ('Chios', 38.343056, 26.140556)
5 ('Corfu', 39.601944, 19.911667)

Second and this is mostly fyi, but you can access both the index of a iterable and the element itself by looping over enumerate() meaning, the following function will print the exact same thing as the one with range(len(data)). This is handy if you need to work with both the element itself and it's index.

def menu(data):
    for the_index, the_element in enumerate(data):
        print(f'{the_index   1} {the_element}')