Full Circuitpython Data to CSV file.

#As part of my new book, tentatively titled "Make: Getting  Started with Circuit Playground Express", one neat trick is writing sensor values to a file on the built-in flash file system. If the values are written as a text file in Comma Separated Values (CSV) format, nearly any word processor or spreadsheet program can read the file.

#The Circuit Python code for reading the onboard temperature and light intensity sensors - feel free to change the readings to other sensors like the accelerometer. Name the file code.py

# Read Temperature and Light Intensity, output as a CSV file
# Mike Barela for Getting Started with Circuit Playground Express
# 2018 MIT License, attribution appreciated

import time
from adafruit_circuitplayground.express import cpx

# Set NeoPixel 0 to green as status of board, NeoPixel 1 to collecting data
cpx.pixels[0] = (0, 90, 0)  # coded red, green, blue
cpx.pixels[1] = (0, 0, 90)  # Pixel 1 blue when collecting data

num_readings = 10  # set to any finite value you want

# we try to open/create the file for append access and write the 
#    heading line. If an error occurs, go to except statement
try: 
    with open("/temp-light.csv", "a") as fp:
        fp.write('Temperature, Light Intensity\n')  # headings
        for x in range(0, num_readings):  
            temp = cpx.temperature
            # do the C-to-F conversion here if you would like
            fp.write(str(temp) + "," + str(cpx.light) + "\n")
            # Change the value of sleep time below in seconds
            # 1 minute=60 sec, 5 mins=300 sec, 1 hour=3600 sec, etc.
            time.sleep(1)
            if cpx.button_a:
                break
        # Done, set NeoPixel 1 to green also
        cpx.pixels[1] = (0, 90, 0)

except OSError as e:
    # set NeoPixel 1 off and blink NeoPixel 0 (status) depending on 
    #    the OS error
    cpx.pixels[1] = (0, 0, 0)           # Blank NeoPixel 1
    message_color = (99, 0, 0)          # Red for generic problem
    if e.args[0] == 28:                 # Device out of space
        message_color = (228, 160, 40)  # set to Orange
    elif e.args[0] == 30:               # Device is read only
        message_color = (181,  90,  0)  # set to Yellow
    for x in range(1, 10):              # Flash message 10 seconds
        cpx.pixels[0] = message_color
        time.sleep(1)
        cpx.pixels[0] = (0, 0, 0)
        time.sleep(1)