f2=sys.argv[1] IndexError: list index out of range while trying to get argument from bash file

Question

I am trying a small project to read the the simple csv file by using bash file and python unforunately its shows

list index out of range error for argv[1]

main.py

import sys
import csv
def main(file_name):

    fp = open(file_name)
    reader = csv.reader(fp)
    points = []
    for row in reader:
        x = row[0]        
        y = row[1]
        print(y)

if __name__ == "__main__":
   if len(sys.argv) > 0:
       file_name = sys.argv[1]
       main(file_name)
   else:
       print "<filename> must be the first argument"

#BAsh file

#!/usr/bin/env bash
chmod +x ./main.py
for f in ./sample_data/*.csv  

do
printf "%-28s" $f
./main.py $f
done

Answer 1

This could happen if $f contains "extra" characters that can be somehow interpreted by BASH, such as & and || . Anyway, it's better to use ./main.py "$f" so $f was interpreted as a single argument.

Consider this example

f="echo hello"
echo $f

This produces: echo hello but not hello as $f is interpreted as an argument.

Answer 2

Maybe your python file must start with #!/usr/bin/python Also it throws error NameError: name 'reader' is not defined because your for loop is not inside main function. After moving that for inside main function your code works.