Question

I’m using Python, and I have a file which has city names and information such as names, coordinates of the city and population of the city:

Youngstown, OH[4110,8065]115436
Yankton, SD[4288,9739]12011
966
Yakima, WA[4660,12051]49826
1513 2410
Worcester, MA[4227,7180]161799
2964 1520 604
Wisconsin Dells, WI[4363,8977]2521
1149 1817 481 595

How can I create a function to take the city name and return a list containing the latitude and longitude of the given city?

fin = open ("miles.dat","r")
def getCoordinates 
cities = []
for line in fin:
    cities.append(line.rstrip())
    for word in line:
        print line.split()

That’s what I tried now; how could I get the coordinates of the city by calling the names of the city and how can I return the word of each line but not letters?

Any help will be much appreciated, thanks all.

Answer 1

I am feeling generous since you responded to my comment and made an effort to provide more info….

Your code example isn’t even runnable right now, but from a purely pseudocode standpoint, you have at least the basic concept of the first part right. Normally I would want to parse out the information using a regex, but I think giving you an answer with a regex is beyond what you already know and won’t really help you learn anything at this stage. So I will try and keep this example within the realm of the tools with which you seem to already be familiar.

def getCoordinates(filename):
    ''' 
    Pass in a filename.
    Return a parsed dictionary in the form of:

    {
        city:  [lat, lon]
    } 
    '''

    fin = open(filename,"r")
    cities = {}

    for line in fin:

        # this is going to split on the comma, and
        # only once, so you get the city, and the rest
        # of the line
        city, extra =  line.split(',', 1)

        # we could do a regex, but again, I dont think
        # you know what a regex is and you seem to already
        # understand split. so lets just stick with that

        # this splits on the '[' and we take the right side
        part = extra.split('[')[1]

        # now take the remaining string and split off the left
        # of the ']'
        part = part.split(']')[0]

        # we end up with something like: '4660, 12051'
        # so split that string on the comma into a list
        latLon = part.split(',')

        # associate the city, with the latlon in the dictionary
        cities[city] = latLong

    return cities

Even though I have provided a full code solution for you, I am hoping that it will be more of a learning experience with the added comments. Eventually you should learn to do this using the re module and a regex pattern.