Loop in a .csv file with IF cases

Question

I am new to Python and can't quite make my if-cases any shorter. Any ideas on how to do that?

import csv
fileheader = csv.reader(open("test.csv"), delimiter=",")
# Defines the header of the file opened
header = fileheader.next()
# Loop into the file
for fields in fileheader:
# For each header of the file, it does the following :
# 1/ Detect if the header exists in the file
# 2/ If yes and if the cell contains datas, it's added to the payload that will be used for an HTTP POST request.
# 3/ If not, it doesn't add the cell to the payload.
 if 'url_slug' in header:
 url_slug_index = header.index('url_slug')
 if fields[url_slug_index] == "":
 print "url_slug not defined for %s" % fields[url_index]
 else:
 payload['seo_page[path]'] = fields[url_slug_index]
 if 'keyword' in header:
 keyword_index = header.index('keyword')
 if fields[keyword_index] == "":
 print "keyword not defined for %s" % fields[url_index]
 else:
 payload['seo_page[keyword]'] = fields[keyword_index]

Answer 1

I would consider wrapping the conditions up inside a function:

def is_header(pattern):
 if pattern in header:
 pattern_index = header.index(pattern)
 if fields[pattern_index]:
 pattern_key = "path" if pattern == "url_slug" else "keyword"
 payload['seo_page[{}]'.format(pattern_key)] = fields[pattern_index] 
 else:
 print("{} not defined for {}".format(pattern, fields[pattern_index])

Because the tests are essentially the same, you could create a common function and pass in the pattern to test against (url_slug or keyword). There is some extra hocus pocus to get pattern_key to be the right thing in order to point to the right key in your seo_page dict (I assume it is a dict?).

Answer 2

Instead of fileheader = csv.reader(open("test.csv"), delimiter=",") you should do

with open("test.csv") as f:
 fileheader = csv.reader(f, delimiter=",")

to ensure that the file is property closed at the end of the script.

Also, why is the reader holding the entire CSV file named fileheader? This seems odd.