current community

your communities

more stack exchange communities

company blog
Stack Exchange Inbox Reputation and Badges
tour help
Code Review Stack Exchange is a question and answer site for peer programmer code reviews. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top
up vote 1 down vote favorite

In Python 3.4, a Counter object called cnt like this: 

Counter({'0200': 3, '3000': 2, '3011': 2, '0210': 1, '4000': 1})

is to be written to a comma-separated file.

I first tried with CSV and DictWriter that I had not used before, but I kept getting misty errors and was pressed for time, so I decided to make this simple version (it works): 

outfile = infile[:-4] + '_freq.csv'  
fp = open(outfile, encoding='utf-8-sig', mode='w')  
fp.write('KMC|freq\n')  
for tag, count in cnt.items():  
    fp.write('{}|{}\n'.format(tag, count))  

fp.close()

Then when I had some time I felt I should learn to use DictWriter and CSV, assuming it'd be 'better' or 'more pythonic'.

That turned into this (works too): 

outfile2 = infile[:-4] + '_freq2.csv'  
with open(outfile2, encoding='utf-8-sig', mode='w', newline='') as f:
                # Note: empty newline to avoid blank lines in the output file 
    fieldnames = ['KMC', 'freq']  
    writer = csv.DictWriter(f, fieldnames=fieldnames, delimiter='|')  
    writer.writeheader()  
    for tag, count in cnt.items():  
        writer.writerow({'KMC': tag, 'freq': str(count)})

The trick with the empty newline to avoid blank lines is from here.

I like the first approach better. I think CSV and DictWriter are intended for much larger amounts of columns than the two small ones I got. But I'm no expert.

Any learned comments?

share|improve this question
up vote 1 down vote accepted

Simplicity

I think that, for an easy task like this, the first version is better as it is considerably simpler while accomplishing the same goal.

It can still be improved though:

Cleaner deletion of file extension

infile[:-4] is probably used to remove the extension from the file, but it is not obvious, I suggest infile.replace(".txt","")( where the extension may be different from txt but you get the idea).

Context managing

It is so easy to forget to close a file, it is better to use with that will close it automatically every time:

with open(outfile, encoding='utf-8-sig', mode='w') as fp:
fp.write('KMC|freq\n')  
for tag, count in cnt.items():  
    fp.write('{}|{}\n'.format(tag, count))

Naming

cnt is a mysterious name, I have no idea what kind of data it may contain, I suggest coming up with a better name.

share|improve this answer

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.