Understanding csv DictWriter syntax in python

Question

I looked at a very useful answer to the previous SO question which can be found here when trying to write a list of dicts to a CSV file. The code I used was:

with open((filename), 'wb') as outfile: write = csv.DictWriter(outfile, keyList) write.writer.writerow(keyList) write.writerows(data) 

where keyList is the list of headers for the csv file.

The code worked fine, which is nice, but I don’t understand why I had to explicitly reference the base instance of writer to write keyList (headers). I tried this line as write.writerow(keyList) and it did not work. I'm curious why this is so, I can better understand how Python DictWriter works.

Is there a cleaner / better way to write this?

Answer 1

It looks like you are relying on undocumented behavior. The DictWriter object DictWriter not have an "official" writer method.

the correct way to output CSV headers is to call

 write.writeheader()