How to return a global variable from a function

[Jake S]

Hello,

I'm trying to extract coordinates based on the name of imagery files. I created a script to do this using functions:

def lat(dd):
    global lat
    lat_lon = dd.split('_')[1]
    if 'N' in lat_lon:
        lat = int(lat_lon[1:3])
    else:
        lat = int(lat_lon[1:3]) * -1

def lon(dd):
    global lon
    lat_lon = dd.split('_')[1]
    if 'W' in lat_lon:
        lon = int(lat_lon[4:]) * -1
    else:
        lon = int(lat_lon[4:])

list = ['ASTMGTM2_N37W110', 'ASTMGTM2_N45E80']
for n in list:
    lat(n)
    lon(n)
    print lat, lon

The script runs correctly for the first value in the list. It returns '37 -110'. However, when it reaches the second value I receive an error:

TypeError: 'int' object is not callable

Does anyone know what I am doing wrong? I am new to python and have never really used the 'global' variable before.

I also tried using the 'return' keyword instead of the global variable:

def lat(dd):
    lat_lon = dd.split('_')[1]
    if 'N' in lat_lon:
        lat = int(lat_lon[1:3])
        return lat
    else:
        lat = int(lat_lon[1:3]) * -1
        return lat
    
def lon(dd):
    lat_lon = dd.split('_')[1]
    if 'W' in lat_lon:
        lon = int(lat_lon[4:]) * -1
        return lon
    else:
        lon = int(lat_lon[4:])
        return lon

list = ['ASTMGTM2_N37W110', 'ASTMGTM2_N45E80']
for n in list:
    lat(n)
    lon(n)
    print lat, lon

This does not error, but I cannot get the numeric values. I receive:

<function lat at 0x03681F30> <function lon at 0x075A9530>

I am currently using Python 2.6 and Windows 7 64-bit. Thank you for your help!

[bvdet]

Use unique identifiers (names) for your functions and values. In function lat() you can eliminate the assignment to identifier lat.

def lat(dd):
    lat_lon = dd.split('_')[1]
    if 'N' in lat_lon:
        return int(lat_lon[1:3])
    else:
        return int(lat_lon[1:3]) * -1

Don't use list for a variable name. Built-in Python function list() will be masked.

Your values can be accessed like this:

seq = ['ASTMGTM2_N37W110', 'ASTMGTM2_N45E80']
for n in seq:
    v1 = lat(n)
    v2 = lon(n)
    print v1, v2

[Jake S]

Thanks, bvdet! That worked like a charm.