[Pitón] ejemplo csv

#!/usr/bin/env python3

import sys
import os
import re
import csv
import pprint
import fcntl

DEBUG_MODE = False


def read_csv(csv_file):
    """parse csv file to dict"""

    if(DEBUG_MODE):print("CSV file (read):" + csv_file)
    
    if(os.access(csv_file,os.F_OK|os.R_OK)): # exist and readable
        csv_f = open(csv_file)
        fcntl.flock(csv_f,fcnt.LOCK_EX) # lock file
        
        reader = csv.reader(csv_f)
        csv_list = list(reader)

        fcntl.flock(csv_f,fcnt.LOCK_UN) # unlock file
        csv_f.close();
    else:
        print("ERROR:%s not exist or unreadable" % (csv_file))
        csv_list = {};
        return csv_list
    if(DEBUG_MODE): pprint.pprint(csv_list)
    return csv_list

def write_csv(csv_file,csv_list):
    """write dict to csv file """

    if(DEBUG_MODE):print("CSV file (write):" + csv_file)
    
    if(os.access(csv_file,os.F_OK|os.W_OK)): # exist and writeable
        csv_f = open(csv_file,'w')
        fcntl.flock(csv_f,fcnt.LOCK_EX) # lock file
        
        writer = csv.writer(csv_f)
        writer.writerows(csv_list)

        fcntl.flock(csv_f,fcnt.LOCK_UN) # unlock file
        csv_f.close();
    else:
        print("ERROR:%s not exist or unreadable" % (csv_file))
        return False
    return True

def main():

    CSV_FILE = "a.csv"
    csv_list_read = read_csv(CSV_FILE)
    csv_list_read[0][0] = "bt"
    write_csv(CSV_FILE,csv_list_read)

if __name__ == '__main__':
    main()