A script to sum byte values (e.g 7TB + 512GB = 7.5TB)

add_bytes.py

#!/usr/bin/env python3

import argparse
import sys

SYMBOLS = ('kilo', 'mega', 'giga', 'tera', 'peta', 'exa', 'zetta', 'iotta')

def get_bytes(data_queue):
    """Parses list of strings, ints or floats representing data amounts (e.g 1MB, 2mb, 3M) to a list of bytes. Parses all types listed in SYMBOLS.

    >>> add_bytes([500, "1.1mb", "23KB"])
    [500.0, 1153433.6, 23552.0]
    """
    output = []
    for item in data_queue:
        if type(item) in (int, float):
            output.append(float(item))
            continue
        if item[-1] in "bB": # we don't need to worry about bytes
            item = item[:-1]
        item = item.lower().strip() # for better matching
        try:
            output.append(float(item))
            continue
        except ValueError:
            pass
        power = 0 # so `if not power` works
        for x, symbol in enumerate(SYMBOLS):
            if symbol[0] in item:
                power = x + 1
        if not power: # string was not a match
            continue
        item = float("".join(c for c in item if c in "0123456789."))
        output.append(item * (1024 ** power))
    return output

def parse_bytes(byte_list, precision=2):
    """ Parses list of ints or floats into summed 'human' amount rounded to 2dp.

    >>> parse_bytes([500, 1153433.6, 23552])
    "1.12MB"
    """
    total = sum(byte_list)
    i = -1
    while total > 1024:
        i += 1
        total = total / 1024
    return ("{:.%sf}{}B" % precision).format(total, SYMBOLS[i][0].upper())

def main():
    parser = argparse.ArgumentParser()
    parser.add_argument("amounts", help="Array of data amounts to be processed", nargs="+")
    parser.add_argument("-p", "--precision", help="Number of decimal places in the output")
    args = parser.parse_args()
    byte_list = get_bytes(args.amounts)
    print(parse_bytes(byte_list, args.precision or 2))
    return 0

if __name__ == "__main__":
    sys.exit(main())