import csv
with open("C:\\Users\\ki386179\\Desktop\\output.csv","r") as f:
reader = csv.reader(f)
for row in reader:
if 'india' in row:
pass
if 'india' not in row:
with open("C:\\Users\\ki386179\\Desktop\\output.csv","w") as f:
writer = csv.writer(f)
writer.writerow('india')
I am trying to achieve something like this , to check for a particular value in a particular column and if not write to it.
You can't write to a file whilst you are in the middle of reading from it. Also, surely you don't want to require every line to contain the string, like your current logic does?
I'm guessing you want to add one line at the end if none of the lines matched:
import csv
seen_string = False
with open("C:\\Users\\ki386179\\Desktop\\output.csv","r") as f:
reader = csv.reader(f)
for row in reader:
if 'india' in row:
seen_string = True
break
if not seen_string:
# Notice append mode; "a" not "w"
with open("C:\\Users\\ki386179\\Desktop\\output.csv","a") as f1:
# Noice this one is f1
writer = csv.writer(f1)
writer.writerow('india')
Maybe notice also that in looks for a substring; if the file contains e.g. amerindian" the code will regard that as a match. Check for string equality with == instead if that's what you want.
You can use r+ mode for both reading and writing. Although it is difficult to understand what you are trying to achieve here, an example code that can do what you're probably trying to achieve is shown below. I put the above code in a script india.py and made it executable (chmod +x india.py)
#!/usr/bin/env python
import sys
from csv import reader, writer
with open(sys.argv[1], "r+") as f:
for row in reader(f):
if "india" in row:
break
else:
writer(f).writerow("india")
A test run
$ cat test_write.csv
us,canada,mexico
france,germany,norway
brazil,argentina,colombia
china,japan,korea
$ ./india.py test_write.csv
$ cat test_write.csv
us,canada,mexico
france,germany,norway
brazil,argentina,colombia
china,japan,korea
i,n,d,i,a
output.csvfile and expected final state of the file