Python: How to close my CSV input and output files? -

hi have been experimenting winston ewert's code example thread.

python: removing duplicate csv entries

but can't close input , output files. doing wrong?

write_outfile.close()

write_infile.close()

traceback (most recent call last): file "duplicates_01.py", line 26, in write_outfile.close() attributeerror: '_csv.writer' object has no attribute 'close'

import csv  write_infile = csv.reader(open('file1.csv', 'r')) write_outfile = csv.writer(open('file2.csv', 'w'))  #write_infile = open('file1.csv', 'r') #f1 = csv.reader(write_infile) #f1 = csv.reader(write_infile, delimiter=' ')  #write_outfile = open('file2.csv', 'w') #f2 = csv.writer(write_outfile) #f2 = csv.writer(write_outfile, delimiter=' ')  phone_numbers = set()  row in write_infile:     if row[1] not in phone_numbers:         write_outfile.writerow(row) #       f2.writerow(row)         phone_numbers.add(row[1])  # write_outfile.close() # write_infile.close() 

file1.csv

user, phone, email joe, 123, joe@x.com mary, 456, mary@x.com ed, 123, ed@x.com 

by doing:

csv.reader(open('file1.csv', 'r')) 

you're passing anonymous file handle csv.reader objects, cannot control when file closed (it's handle needs closed, not csv.reader object)

the close method must apply file handle (csv reader/writer objects can work on lists, iterators, ..., can't have close method) do:

fr = open('file1.csv', 'r') 

and

csv.reader(fr) 

then

fr.close() 

or use context manager:

with open('file1.csv', 'r') fr:     csv.reader(fr) 

and file closed leave context

aside: there's catch when creating csv files on python versions. using handle open('file2.csv', 'w') may cause problems (blank lines inserted). compatible & robust way can read this q&a