"List index out of range" error when sorting data in csv files using python

Question

I have three .csv files and i would like python to sort the data in them. i have this code but when i launch it an error occurs. An error occurs in this line sort = sorted(csv1, key= operator.itemgetter(1)). The number at the end suppose to choose the column but it doesn't. I had this program on mac and it worked but when i launched it on windows it stopped working.

import operator
import csv

decision= input("How would you like to view information? Type score or surname.")
decision1= input("What calss would you like to see? Type class1 or class2 or class3.")


if (decision == 'score' and decision1 == 'class1'):
    sample = open('class1.csv', 'r')
    csv1 = csv.reader(sample,delimiter = ',')
    sort = sorted(csv1, key= operator.itemgetter(0))
    for eachline in sort:
        print (eachline)

if (decision == 'surname' and decision1 == 'class1'):
    sample = open('class1.csv', 'r')
    csv1 = csv.reader(sample,delimiter = ',')
    sort = sorted(csv1, key= operator.itemgetter(1))
    for eachline in sort:
        print (eachline)

if (decision == 'score' and decision1 == 'class2'):
    sample = open('class2.csv', 'r')
    csv1 = csv.reader(sample,delimiter = ',')
    sort = sorted(csv1, key= operator.itemgetter(0))
    for eachline in sort:
        print (eachline)

if (decision == 'surname' and decision1 == 'class2'):
    sample = open('class2.csv', 'r')
    csv1 = csv.reader(sample,delimiter = ',')
    sort = sorted(csv1, key= operator.itemgetter(1))
    for eachline in sort:
        print (eachline)

if (decision == 'score' and decision1 == 'class3'):
    sample = open('class3.csv', 'r')
    csv1 = csv.reader(sample,delimiter = ',')
    sort = sorted(csv1, key= operator.itemgetter(0))
    for eachline in sort:
        print (eachline)

if (decision == 'surname' and decision1 == 'class3'):
    sample = open('class3.csv', 'r')
    csv1 = csv.reader(sample,delimiter = ',')
    sort = sorted(csv1, key= operator.itemgetter(1))
    for eachline in sort:
        print (eachline)

yoshiwaan · Accepted Answer · 2015-03-20 16:41:12Z

2

Something like this?

import operator
import csv

sorter = raw_input("Set sort method (score or surname): ")
classNumber = raw_input("Set class number (1, 2 or 3): ")

def print_sorted(sortMethod, classNumber):
    classFile = 'class' + str(classNumber) + '.csv'
    with open(classFile, 'r') as fh:
        csvData = csv.DictReader(fh)
        sortedCsvData = sorted(csvData, key=operator.itemgetter(sortMethod))
        for line in sortedCsvData:
            print line

print_sorted(sorter, classNumber)

You would want to add some sort of validation of the input set by the user before running the function though.

This won't error out if there is a value missing for a column.

Edit to say: If you are using python 3 then you need to change raw_input() above to be input()

edited Mar 20, 2015 at 16:41

answered Mar 20, 2015 at 16:17

yoshiwaan

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4 Comments

Alekasndr Kataev Over a year ago

It still gives me an error Traceback (most recent call last): File "H:/Computing/sorting.py", line 2, in <module> import csv File "H:/Computing\csv.py", line 13, in <module> in_txt = csv.reader(open(txt_newfile, "rb"), delimiter = '\t') AttributeError: 'module' object has no attribute 'reader'

yoshiwaan Over a year ago

Did you use the code above? I'm not using csv.reader it's using csv.DictReader, so that error doesn't make sense. Why are you specifying a delimeter='\t' if in the original example you used a comma? I don't think that's the same thing you're running.

yoshiwaan Over a year ago

Sorry, fixed up a syntax error as well, so copy again.

yoshiwaan Over a year ago

Any luck trying this out?

mway · Accepted Answer · 2015-03-20 16:27:06Z

1

It sounds like at least one of your rows is missing a value for column 1. csv.reader(sample) returns a generator of lists, where each list corresponds to a row, and the length of each list corresponds to the number of comma-separated values in the given row. So a file with data like this:

   John,Smith
   Joe
   Jane,Doe

Would give you (["John", "Smith"], ["Joe"], ["Jane", "Doe"]) when parsed by csv.reader.

The sorted function is breaking when operator.itemgetter tries to access an index (column) from one of the lists (rows) that doesn't exist. If you were sorting on column 1 in the above example, your code would break because there is only 1 element in the list ["Joe"]

answered Mar 20, 2015 at 16:27

mway

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