Wsrtjtyk

I have some GPS coordinate data e.g.

38 41'13.2"N

96 30'23.4"E 

How can I check it has a constant format? Sometimes the data is like:

38 41.2342

96 30.1211

I tried using re, but the punction inside the string makes it difficult to pass through.

Ideal format is XX XX'XX.X"(E or N)

I tried

import re

r = re.compile(".* .*'.*..*"N")

if r.match('48 46'55.3"N') is not None:

   print 'matches'

taken from here

You haven't escaped your quotes in your example. Notice the " on line 2, and the ' on line 3. This is important so that python knows the quote is part of the string, and not terminating it.

I have also used a slightly more explicit pattern.

import re

r = re.compile("^d{2} d{2}'d{2}.d{1}"[EN]$")

if r.match('48 46'55.3"N') is not None:

    print 'matches'

Your punctuation problems are (1) you need to escape the . with a backslash when you want to match the actual decimal point, otherwise it matches any character; and (2) you need to escape the double-quote or otherwise prevent it from terminating your string.

The best way to write this as a readable debuggable regex is to use a Python "raw" string r"like this" which allows backslashes without escaping, and furthermore to triple-quote it, which lets you to use both ' and " inside it without escaping. And since triple-quoted strings allow multi-line expressions, you could even compile in VERBOSE mode, allowing whitespace and comments. Debuggability of your subsequent matching/extraction code is also improved if you use the (?P<...>) named-group syntax in your regex—groups will then be accessible by meaningful names, in the match object's groupdict() output. Taken all together, that gives us:

PATTERNS = [ # a list of alternative acceptable formats



    re.compile( r"""              

        ^s*                      # beginning of string (optional whitespace)

        (?P<degrees>d+)[s]      # integer number of degrees (NB: might be desirable to insert the degree symbol into the square brackets here, to allow that as a possibility?)

        (?P<minutes>d+)'         # integer number of minutes

        (?P<seconds>d+(.d*)?)" # seconds, with optional decimal point and decimal places

        (?P<axis>[NE]?)           # optional 'N' or 'E' character (remove '?' to make it compulsory)

        s*$                      # end of string (optional whitespace)

    """, re.VERBOSE ),            



    re.compile( r"""

        ^s*                      # beginning of string (optional whitespace)

        (?P<degrees>d+)[s]      # integer number of degrees (NB: might be desirable to insert the degree symbol into the square brackets here, to allow that as a possibility?)

        (?P<minutes>d+(.d*)?)  # minutes, with optional decimal point and decimal places

        (?P<axis>[NE]?)           # optional 'N' or 'E' character (remove this line if this is never appropriate in this format)

        s*$                      # end of string (optional whitespace)

    """, re.VERBOSE ),            



]