comparing integers and fractions

[tantony]

I'm writing a script to get data from an aviation website. The problem is that, sometimes the value of 'visibility' could be an integer such as 10, but sometimes, the value of 'visibility' could be a fraction such as 10 3/4, or 10 1/2 depending on the visibility at the airport. Because of that, I'm getting an error when the value is a fraction. How can I fix this?

    for x in metar.split():
        if 'SM' in x:
            visibility = x.replace('SM', '')
            visibility = int(visibility)

        if 'SCT' in x or 'BKN' in x:
            ceiling = x.replace('SCT', '').replace('BKN', '')
            ceiling = int(ceiling)

    if visibility >= 10:
        flight_conditions = 'VFR'
        print(icao,name,flight_conditions)
    else:
        flight_conditions = 'IFR'
        print(icao,name,flight_conditions)

visibility = int(visibility)
ValueError: invalid literal for int() with base 10: '3/4'

---

I know I have

visibility = int(visibility)

, but how can I make it to accept fractions?

[newbieAuggie2019]

The problem is that, sometimes the value of 'visibility' could be an integer such as 10, but sometimes, the value of 'visibility' could be a fraction such as 10 3/4, or 10 1/2 [ ... ] Because of that, I'm getting an error when the value is a fraction. How can I fix this?

Hi!

I've just had a similar problem with a very simple program, and then I learned that while for a whole number, as a string or not, the int() function returns the same value:

Output:
>>> int('3')
3
>>> int(3)
3

the same is not done, when the number is not a whole number:

Output:
>>> int(5.7)
5
>>> int('5.7')

Error:
Traceback (most recent call last):
  File "<pyshell#38>", line 1, in <module>
    int('5.7')
ValueError: invalid literal for int() with base 10: '5.7'

So make the necessary modifications for the number to be used without the quotes.

Ah, also remember that if the numbers follow the format 10 3/4, that's also going to give you an error:

Output:
>>> int(10 3/4)

Error:
SyntaxError: invalid syntax

Output:
>>> int(10 * 3/4)
7

All the best,

[DeaD_EyE]

Just trying stupidly until it works

from fractions import Fraction


def to_float(value):
    value = value.strip() # remove whitespaces from left and right side
    try:
        value = float(value)
    except ValueError:
        # is not an float, trying next
        pass
    else:
        # is an float, just return it
        return value
    try:
        left, right = value.split()
        left = float(left)
        frac = Fraction(*map(int, right.split('/')))
    except ValueError:
        # hm, maybe only a fraction, let's try this
        pass
    else:
        # was ok, return it
        return left + frac
    try:
        frac = Fraction(*map(int, value.split('/')))
    except ValueError:
        # also not a single fraction
        pass
    else:
        return frac

Example:

Output:
In [26]: values = ['10 3/4', '10 1/2', '6', '42', 'garbage']  # parsed values as str          

In [27]: [to_float_or_int(v) for v in values]                                                 
Out[27]: [Fraction(43, 4), Fraction(21, 2), 6, 42, None]

[tantony]

I wrote a function that converts fractions to float, and so far it seems like its working. Similar to what DeaD_EyE had

def fraction_to_float(num):
    if ' ' in num:
        convert = num.split(' ')
        fraction = convert[1].split('/')
        divide = float(fraction[0]) / float(fraction[1])
        divide = float(convert[0]) + divide
        return round(divide, 2)
    else:
        num = num
        return num

print(fraction_to_float('1 1/4'))
1.25


def fraction_to_float(num):
    if ' ' in num:
        convert = num.split(' ')
        fraction = convert[1].split('/')
        divide = float(fraction[0]) / float(fraction[1])
        divide = float(convert[0]) + divide
        return round(divide, 2)
    else:
        num = num
        return num

print(fraction_to_float('1'))
1