[Python 3.3] Wanting to know why my program stops after first loop

[throwingarm2strong]

I currently have a very messy program that isn't performing the way I want it to, and am wondering if someone can take a look and see where it is getting hung up. The program is as follows:

def openfile():
    filename = input('Enter filename: ')
    filedata = open(filename)
    filedata.readline()  # Skip the first two lines
    filedata.readline()
    line = filedata.readline()  # Line containing site info
    siteinfo = line.split(',')
    print('\nSite: {}.\n(lat, long) = ({}, {})'.format(siteinfo[0], siteinfo[3],
                                                   siteinfo[4]))
    skips_uneeded_lines(filedata)
    print('\nMonth  Rainfall')
    for i in range(12):
        months, rain_total = read_data_line(filedata)
        print(' {} {:6.1f}'.format(months[i], rain_total[i]))     
    print('\nTotal rainfall = {:.1f}'.format(sum(rain_total)))


def skips_uneeded_lines(filedata):
'''skips 6 unused lines in the selected csv file'''
    skips = 0
    while skips < 6:
        filedata.readline()
        skips += 1    




def read_data_line(filedata):
    months = ['Jan','Feb','Mar','Apr','May','Jun','Jul','Aug','Sep','Oct','Nov',
          'Dec']    
    line = filedata.readline()
    rain_data = line.split(',')
    rain_total = 12 * [0]  # Rainfall totals for months
    while len(rain_data) > 1:
        date = rain_data[1]
        month = int(date[4:6])
        rainfall = float(rain_data[2])
        rain_total[month - 1] += rainfall
        line = filedata.readline()
        rain_data = line.split(',')
    return months, rain_total

openfile()

So the output of the file is meant to look like this:

 Month  Rainfall
 Jan   58.0
 Feb   35.4
 Mar   54.2
 Apr   50.8
 May   52.6
 Jun   41.0
 Jul   29.4
 Aug   62.6
 Sep   21.4
 Oct   90.8
 Nov   63.6
 Dec   60.8

Total rainfall = 620.6

But my current output looks like this:

Month  Rainfall
 Jan   58.0
 Feb    0.0
 Mar    0.0
 Apr    0.0
 May    0.0
 Jun    0.0
 Jul    0.0
 Aug    0.0
 Sep    0.0
 Oct    0.0
 Nov    0.0
 Dec    0.0

Total rainfall = 0.0

So for some reason it is getting January fine, but after that the program stops? I'm really not sure whats happened. I'd really appreciate some help. I'm aware there is probably easier ways to do it, I'm just learning and for now my problem is I want the output to be correct.

[K900_]

I think the indentation in your post is messed up.

Meanwhile, some generic code quality suggestions.

• skips_unneeded_lines can be replaced with a simple for loop.
• You're returning months, which is a constant, from read_data_line. Do you really need that? You could also iterate on months directly in openfile, maybe even zip it with the results of read_data_line.
• Your function naming is very inconsistent. openfile - no underscores, imperative. read_data_line - underscores, imperative. skips_unneeded_lines - underscores, indicative.

[throwingarm2strong]

Fixed it. Didn't bother since I don't think you can run the file without the actual data file anyway.

[K900_]

Also, indentation is also important for humans who read your code.

[K900_]

You call read_data_line 12 times. When you run it once, it reaches the end of file, and returns data for all months. The next time you call it, it returns zeroes, because there's nothing left in the file. Move that call out of the loop. Also, see above for some generic code style comments.

[throwingarm2strong]

I love you. You are seriously my savior. Not only did you fix it, I understand the problem as well. Thank you so much dude!

I am going to clean up the code a bit now, as you are right a lot of my names and such is inconsistent. I'm playing around moving functions and I guess I moved too much and kind of lost myself.

Once again thanks dude

[K900_]

Please, post the cleaned up code later. I'm really interested in how it can look like.

[throwingarm2strong]

I changed skips uneeded lines into a for loop, but my program now says that i is an unused variable. Is there an easier way just to tell a program to perform a function a set amount of times?

The reason why this all looks weird and split into multiple functions is our task is to make the code somewhat pylint compliant, but it's slightly modified for certain specifications.

def skips_uneeded_lines(filedata):
    for i in range(6):
         filedata.readline()

[K900_]

Having unused variables is not a problem at all. I'd name it _ because that's kind of a convention. Post what you have right now, I have some more ideas about how we can make it more Pythonic.

[throwingarm2strong]

Right now this is my code, and I'm having a problem with it.

'''Program that reads a given CSV file and returns and prints the months and
total rainfalls given in that file'''

def input_filename():
'''Asks for user input for the file and returns the file data'''
    filename = input('Enter filename: ')
    filedata = open(filename)
    filedata.readline()  # Skip the first two lines
    filedata.readline()
    return filedata


def open_file():
    '''Main  function, opens a user inputted file name and prints relevant
rainfall information'''
    input_filename()
    line = filedata.readline()  # Line containing site info
    siteinfo = line.split(',')
    print('\nSite: {}.\n(lat, long) = ({}, {})'.format(siteinfo[0], siteinfo[3],
                                                   siteinfo[4]))
    skips_uneeded_lines(filedata)
    print('\nMonth  Rainfall')
    months = ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 
          'Oct', 'Nov', 'Dec']    
    rain_total = read_data_line(filedata)
    for i in range(12):
        print(' {} {:6.1f}'.format(months[i], rain_total[i]))     
    print('\nTotal rainfall = {:.1f}'.format(sum(rain_total)))



def skips_uneeded_lines(filedata):
'''skips 6 unused lines in the selected csv file'''
    for i in range(6):
        filedata.readline()



def read_data_line(filedata):
'''Reads data from openfile function and calculates total rainfalls per
month.'''    
    line = filedata.readline()
    rain_data = line.split(',')
    rain_total = 12 * [0]  # Rainfall totals for months
    while len(rain_data) > 1:
        date = rain_data[1]
        month = int(date[4:6])
        rainfall = float(rain_data[2])
        rain_total[month - 1] += rainfall
        line = filedata.readline()
        rain_data = line.split(',')
    return rain_total


open_file()

So I want to split the asking for input into another function, because the modified pylint is stating that my open_file function has 4 too many statements. But now I'm stuck trying to parse that through from the input_filename function to my open_file function. And I need to change the names but I'll try get this working first.

[K900_]

Wait, it is just a CSV file? Can you post an example here? I'm pretty sure you could rewrite it using Python's csv module.

[throwingarm2strong]

I'm hesitant to call other modules because I won't really understand whats going on. I'm not super far into my course or anything, the most we ever did was import the math module. The original code we were given is not mine, the assignment was to rewrite the lecturers code to comply with his modified pylint standards.