FileIO

Write and read files using MircoPython.

Write to File

 1 # write 100 random values to a file
 2 import random
 3 import os
 4 
 5 file = open('datafile01.txt', 'a')
 6 for i in range(100):
 7     random_integer = random.randint(1, 1000)
 8     file.write(str(i) + "; " + str(random_integer) + "\n")
 9     print(str(i) + "; " + str(random_integer))
10 file.close()

Or and alternative: here the file is closed automatically when the block inside the with statement is exited.

 1 # write 100 random values to a fileimport random
 2 
 3 # Use a context manager to handle the file
 4 import random
 5 import os
 6 
 7 with open('datafile02.txt', 'a') as file:
 8     for i in range(100):
 9         random_integer = random.randint(1, 1000)
10         file.write(str(i) + "; " + str(random_integer) + "\n")
11         print(str(i) + "; " + str(random_integer))

Read to File

1 # Read the file 
2 import os
3 
4 with open('datafile01.txt', 'r') as file:
5     for line in file:
6         columns = line.strip().split('; ')
7         print(columns[1] + " is the value at: " + columns[0])

Get and Put Files Between Microcontroller and Local Machine

Files can be copied via the command line tool Adafruit MicroPython tool (ampy).

pip3 install adafruit-ampy

To get a file from the microcontroller to the local machine, use the following command:

ampy --port /dev/tty.usbmodem143101 get FILE_NAME_OF_REMOTE_FILE.FILE_EXTENSION FILE_NAME_FOR_THE_LOCAL_FILE.FILE_EXTENSION

To put a file to the microcontroller from the local machine, use the following command:

ampy --port /dev/tty.usbmodem143101 put FILE_NAME_OF_THE_LOCAL_FILE.FILE_EXTENSION FILE_NAME_FOR_REMOTE_FILE.FILE_EXTENSION