How to append new rows in CSV file python?

Question

I'm using python 2.7 and I have a program that when I take picture from the camera ,the data(phase,date,time,name of image) will be stored in CSV file each time when the image being capture. This is the csv file looks like when the short code below executed. https://i.sstatic.net/hzMTe.png

As you can see the "headers" which are 'Phase', 'Date', 'Time','Name' will be printed out again in the next line when the image being capture.

I want the headers just print one time on the top of csv file. As I strolling around some websites there is [newline=''] keyword that should work but as I'm using python 2.7 it's not possible.

Any help would be greatly appreciated.

import csv

with open('data.csv', 'a') as f:

                fieldnames = ['Phase', 'Date', 'Time','Name']
                thewriter = csv.DictWriter(f, fieldnames = fieldnames)
                thewriter.writeheader()

                thewriter.writerow({'Phase': _phase, 'Date' : 
                 _currentDT.date(), 'Time' : _currentDT.time(),
                                    'Name' : _nameImage })

You can maybe compare the first row and see if headers are added and not add it the second time — Z.Amir
– Z.Amir, Commented May 10, 2019 at 10:56

Z.Amir · Accepted Answer · 2019-05-13 09:26:42Z

0

If you want a simple solution you can do something like this (not the most efficient solution)

import csv

with open('data.csv', 'r+') as f:
    reader = csv.reader(f)
    row1 = []

    try:
        row1 = next(reader)
    except StopIteration:
        print("No data is written to file yet")

    fieldnames = ['Phase', 'Date', 'Time', 'Name']
    thewriter = csv.DictWriter(f, fieldnames=fieldnames)

    if row1 != fieldnames:
        thewriter.writeheader()

    thewriter.writerow({'Phase': _phase, 'Date' : 
     _currentDT.date(), 'Time' : _currentDT.time(),'Name' : _nameImage })

edited May 13, 2019 at 9:26

answered May 10, 2019 at 11:40

Z.Amir

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11 Comments

frankenstein Over a year ago

sorry for late reply, but your code doesn't work, it somehow isn't write anything, just an empty csv file.

frankenstein Over a year ago

the code runs without any error, but somehow the csv file was empty as this link. imgur.com/r8bnUWO

Z.Amir Over a year ago

StopIteration exception was thrown which I was not handling previously.

frankenstein Over a year ago

I have updated your code but when I run it it's not even write the file which is data.csv

frankenstein Over a year ago

but I have tried to create a "data.csv" by hand before I execute the code , and the data is written lol , as this imgur.com/KLerJUP

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