Parsing with Python

Question

I am attempting to parse a file. Currently, I have this file:

word1 52345325
word2 12312314
word3 7654756
word4 421342342

I am attempting to store word1 word2 word3 and word4 into an array and the numbers adjacent to those words into another array.

So if i say a[0] i should get word1, and if I say b[0] i should get 52345325 and so on.

I was thinking about making a key-valued pair dictionary object but that may be a little complex at this point as I am just getting into python.

I currently am doing this but of course, it ain't working :P

def csvStringParser():
    a = {}
    b = {}
    i = 0
    f = open('/Users/settingj/Desktop/NOxMultiplier.csv')
    for line in f.readlines():
    reader = csv.reader(line.split('\t'), delimiter='\t')
        for row in reader:
            #print '\t'.join(row)                                                                                                                                                                                                                                             
            #print i                                                                                                                                                                                                                                                          
            a[i] = '\t'.join(row)
            b[i] = '\t'.join(row)
            print a[i]
            print b[i]
            i+=1

This is honestly my first hour of using python. I could easily do this in C++ but I'm am currently just trying to learn python to understand it's greater benefits/simplicity over c++.

Answer 1

import csv

a = {}
with open('/Users/settingj/Desktop/NOxMultiplier.csv') as f:
    reader = csv.reader(f, delimiter='\t')
    for row in reader:
        a[row[0]] = row[1]
print a

For two arrays:

a = []
b = []
with open('/Users/settingj/Desktop/NOxMultiplier.csv') as f:
    reader = csv.reader(f, delimiter='\t')
    for row in reader:
        a.append(row[0])
        b.append(row[1])
print a
print b

of even just similar solution with the zip:

with open('/Users/settingj/Desktop/NOxMultiplier.csv') as f:
    a, b = zip(*csv.reader(f, delimiter='\t'))
print a
print b

Answer 2

Ok, in fact, there is only one line of code:

a, b = zip(*(map(lambda x: x.rstrip('\n\r').split('\t'), open('file.csv').readlines())))

Some links:

• http://docs.python.org/2/library/functions.html#map
• http://docs.python.org/2/library/functions.html#zip
• http://docs.python.org/2/library/stdtypes.html#str.rstrip
• http://docs.python.org/2/library/stdtypes.html#str.split

Answer 3

Here's my implementation that does what you describe with the input you describe: #!/usr/bin/python

def csvStringParser(filename):
    a = []
    b = []
    f = open(filename)
    for line in f.readlines():
        tok = line.split()
        a.append(tok[0])
        b.append(tok[1])
    print a
    print b

if __name__=="__main__":
    csvStringParser('temp.txt')

You could use other separators in split() such as split('\t') if you use tab delimiters, but you probably don't need the csv package for what you describe.