Python: Write 3 dimensional array to CSV file

Question

I am trying to write a program that takes in data from a JSON file, puts it into arrays, and then writes the arrays into a CSV file for human-readability. I am already parsing the JSON file and the array comes out looking like this:

sensorTest = [[[1, 2, 3],
               [4, 5, 6],
               [7, 8, 9],
               [10, 11, 12]],
              [[13, 14, 15],
               [16, 17, 18],
               [19, 20, 21],
               [22, 23, 24]]]

I want this to be written to a CSV file so that the elements of each list are placed in their own column like this: The desired CSV output

Instead, out of everything I have tried, I keep getting something that essentially just places all the array elements in the first column like this: Bad output

I'll attach my code below.

import json
import csv
from os import walk
from os import path
import matplotlib.pyplot as plt
import numpy as np
from datetime import datetime

if __name__ == "__main__":
sensorBoard = [0, 1]
    with open("./Data/sensorData.csv", "w", encoding='utf8', newline='') as csvfile:
        csvfile.write("C1,C2,C3,C4,C5,C6,C7,C8\n")
        hrd = csv.writer(csvfile)   # hrd is human-readable data
        for board in sensorBoard:  # loop through element number of lists
            print(board)
            print(sensorTest[board])
            # print(sensorTest[board][0])
            # print(sensorTest[board][1])
            for channelIndex, channelVals in enumerate(sensorTest[board]):  # this grabs the set of values for the channel
                print(sensorTest[board][channelIndex])
                # hrd.writerow([str(sensorTest[board][channelIndex])])
                for valIndex, val in enumerate(sensorTest[board][channelIndex]):
                    hrd.writerow([str(val)])

Scott Hunter · Accepted Answer · 2022-06-24 16:43:24Z

1

Let Python do more of the work for you:

data = sensorTest[0]+sensorTest[1]
with open("output.csv", "w", encoding='utf8') as csvfile:
    hrd = csv.writer(csvfile)
    hrd.writerow(["C%d"%d for d in range(1,1+len(data))])
    for r in zip(*data):
        hrd.writerow(r)

answered Jun 24, 2022 at 16:43

Scott Hunter

50k12 gold badges64 silver badges107 bronze badges

Sign up to request clarification or add additional context in comments.

4 Comments

embedtime Over a year ago

holy cow you're a godsend. is there a way to do it so that it doesn't skip a row between the values?

Scott Hunter Over a year ago

What do you mean by "skip a row between the values"? Maybe try specifying newline in open?

embedtime Over a year ago

When I open the csv file in excel it looks like each array element skips a row: imgur.com/a/pfOc1R3. Edit: looks like adding newline='' to open fixed it. Thanks again!

Scott Hunter Over a year ago

Using newline="\n" worked for me.

Collectives™ on Stack Overflow

Python: Write 3 dimensional array to CSV file

1 Answer 1

4 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

4 Comments

Your Answer

Sign up or log in

Post as a guest