Writing logs to CSV file (Python, C language)

In my work, I had to take data continuously → write it to a CSV file and take a log. I tried to summarize it as a memorandum.

environment

OS：Raspbian Buster 10 Software used: Code-OSS (headmelted) 1.44.0

Program flow

Create an empty CSV file in the same hierarchy as the program and write the log to it. Add the date first, like "AD / month / day hour: minute: second, (data 1), (data 2) ..." List the data you want to record behind, separated by commas.

Python

csvWrite.py

import csv
import datetime

n = 0
try:
    with open('logger.csv', 'a') as f:
        #Write log 10 times
        while n < 10:
            #Date Time
            now = datetime.datetime.now()
            nowTime = '{0:%Y/%m/%d %H:%M:%S}'.format(now)

            #Data group
            data1 = 'data1'
            data2 = 'data2'
            data3 = 'data3'

            writeStr = nowTime + ',' + data1 + ',' + data2 + ',' +data3
            writeStr = writeStr.split(',')

            #Confirmation of the written character string
            #Example:'2020/03/06 15:00:00','data1','data2','data3'
            print('writeStr = %s' % writeStr)

            writer = csv.writer(f, quoting=csv.QUOTE_NONNUMERIC)
            writer.writerow(writeStr)

            n += 1

except FileNotFoundError as e:
    print(e)
except csv.Error as e:
    print(e)

C language

csvWrite.c

#include <stdio.h>
#include <time.h>

FILE *fp;
char *fname = "logger.csv";
struct tm tm;

int main(void)
{
    struct tm tm;
    time_t t;

    //Data group
    char data1[] = "data1";
    char data2[] = "data2";
    char data3[] = "data3";

    //Open the file (if it doesn't exist, it will be created automatically)
    fp = fopen(fname, "a");
    if(fp == NULL){
        printf("file can't open¥n");
        return -1;
    }

    //Write log 10 times
    for(int n = 0; n < 10; n++){
        //Date Time
        t = time(NULL);
        localtime_r(&t, &tm);

        fprintf(fp, "\"%04d/%02d/%02d %02d:%02d:%02d\",",
            tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
            tm.tm_hour, tm.tm_min, tm.tm_sec);
        fprintf(fp, "\"%s\",\"%s\",\"%s\"\n", data1, data2, data3);

        //Confirmation of the written character string
        //Example:"2020/03/06 15:00:00","data1","data2","data3"
        printf("writeStr = \"%04d/%02d/%02d %02d:%02d:%02d\",\"%s\",\"%s\",\"%s\"\n", 
            tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
            tm.tm_hour, tm.tm_min, tm.tm_sec, data1, data2, data3);
    }

    fclose(fp);
    return 0;
}

Summary

When I am developing IoT, I leave a log on the server, but when I can not connect to the Internet The feeling of despair when the log disappears during that time is amazing, so I would like to create a CSV file on the SD card and save it diligently in this way.