binpack.py

# binpack.py

# Usage: binpack.py binsize csv_file
#
# binsize is the size of the bins to be used
# csv_file is the file containing the data to be packed
#
# The CSV file should have the following format:
#   name, size
#   name, size
#   ...
#   name, size
#
# The output is a table of bins mapping to the items in each bin.

import sys
import csv
import math

# a non-optimal bin packing algorithm
def pack(binsize, items):
    items.sort(key=lambda item: item[1], reverse=True)
    bins = []
    for item in items:
        name = item[0]
        size = item[1]
        for bin in bins:
            if bin[0] + size <= binsize:
                bin[0] += size
                bin[1].append(name)
                break
        else:
            bins.append([size, [name]])
    return bins

# read the input file
def read_input(filename):
    items = []
    with open(filename, 'r') as f:
        reader = csv.reader(f)
        for row in reader:
            items.append([row[0], int(row[1])])
    return items

# write the output file
def write_output(bins):
    for i in range(len(bins)):
        for item in bins[i][1]:
            print('bin' + str(i) + ', ' + item)

# main function
def main():
    if len(sys.argv) != 3:
        print('Usage: binpack.py binsize csv_file')
        sys.exit(1)
    binsize = int(sys.argv[1])
    items = read_input(sys.argv[2])
    bins = pack(binsize, items)
    write_output(bins)