Using Command line to select a file, reading the file and storing contents as a matrix (PYTHON, Visual Studio)

Question

I have a file with N rows and M columns. I would like to use the command line (python) to specify the file and then store its contents into a matrix in this form [0,0,0],[0,0,0]...

I have this so far, but when I run in through terminal, it does not ask for the text file.

import sys

def read_data(filename):
    with open(filename, 'r') as f:
        data = [[int(num) for num in line.split(',')] for line in f]
    return data

def main():
    if len(sys.argv) < 2:
        print("Usage: {0} <Data Points>".format(sys.argv[0]))
        sys.exit(1)

    file1 = sys.argv[1]

    data_points = read_data(file1)
    print(data_points)

Answer 1

You should pass the file path as an argument when calling your program.

python script.py /myfile

Or whatever arguments your script.py file needs.

Answer 2

Your script does not call the main() function. We define the main() function, but it will not run until called. I added a call to the main() function at the bottom of the script.

import sys

def read_data(filename):
    with open(filename, 'r') as f:
        data = [[int(num) for num in line.split(',')] for line in f]
    return data

def main():
    if len(sys.argv) < 2:
        print("Usage: {0} <Data Points>".format(sys.argv[0]))
        sys.exit(1)

    file1 = sys.argv[1]

    data_points = read_data(file1)
    print(data_points)

main()

When you run the script, you will want to run it on the command line using a command that looks similar to this:

$ python3 myscript.py mydata.csv

Where:

• myscript.py is the name of your script
• mydata.csv is the name of your data file