Programing Language: latitude-longitude-decimalize

[Ian Kelly]

On Tue, Nov 29, 2011 at 3:53 PM, Xah Lee <xahlee at gmail.com> wrote:
> fun programing exercise. Write a function “latitude-longitude-
> decimalize”.
>
> It should take a string like this: 「"37°26′36.42″N 06°15′14.28″W"」.
> The return value should be a pair of numbers, like this: 「[37.44345
> -6.25396]」.
>
> Feel free to use perl, python, ruby, lisp, etc. I'll post a emacs lisp
> solution in a couple of days.

For Python 3:

import re

def latitude_longitude_decimalize(string):
    regex = r"""(\d+)\xb0(\d+)'([\d+.]+)"([NS])\s*(\d+)\xb0(\d+)'([\d+.]+)"([EW])"""
    match = re.match(regex, string)
    if not match:
        raise ValueError("Invalid input string: {0:r}".format(string))
    def decimalize(degrees, minutes, seconds, direction):
        decimal = int(degrees) + int(minutes) / 60 + float(seconds) / 3600
        if direction in 'SW':
            decimal = -decimal
        return decimal
    latitude = decimalize(*match.groups()[:4])
    longitude = decimalize(*match.groups()[4:8])
    return latitude, longitude