March 31, 2013
Over the Easter weekend I spent some time porting Zach Holman's excellent boom tool to Python.
The source is over at Github.
You can install it like this:
$ pip install bam
Or install the latest development version like this:
$ pip install git+git://github.com/mrben/bam.git
And use it like this:
A full list of command is available on the GitHub project page.
June 27, 2012
A Global Resource Identifier, or GRid, is used in the music industry to uniquely identify digital data such as sound recordings. Like barcodes, the last digit is a check digit to verify that the preceding digits were correct.
Calculating the check digit for a GRid is a little more of an obscure need than barcodes, but this Python code snippet will save whomever needs to do it in Python a bunch of time!
def calculate_grid_check_digit(grid): """ Assumes `grid` is 17 characters long and missing the check digit. """ def _mod_36(i): """ A modified modulus function is used by the algorithm. """ m = i % 36 return 36 if m == 0 else m grid = grid.upper() lookup_values = ['0','1','2','3','4','5','6','7','8','9', 'A','B','C','D','E','F','G','H','I','J', 'K','L','M','N','O','P','Q','R','S','T', 'U','V','W','X','Y','Z'] p_list =  s_list =  for j, c in enumerate(grid): c_val = lookup_values.index(c) s_list.append(p_list[j]%37+int(c_val)) p_list.append(_mod_36(s_list[j]) * 2) i = 0 while 1: if _mod_36(p_list[-1]%37 + i) == 1: break; i += 1 return lookup_values[i]
June 1, 2012
Here is some Python to validate barcodes (tested with EAN-13s). Someone should find it useful.
get_check_digit() will generate the valid check digit for the first part of a barcode. While
is_valid_barcode() will check the final digit of a barcode against the generated check digit.
import math def get_check_digit(b): """ Returns the check digit for a barcode. It is assumed that the check digit is missing from the input. """ sum = 0 for x, c in enumerate(b[::-1]): if (x + 1) % 2: sum += int(c) * 3 else: sum += int(c) return str(int(math.ceil(sum / 10.0) * 10) - sum) def is_valid_barcode(b): """ Checks the last digit of a barcode matches the calculated check digit. """ return get_check_digit(b[0:-1]) == b[-1] test_data = ( # Valid barcodes ('9771473968012', True), ('0123456789012', True), ('1234567890128', True), # Invalid barcodes ('9771473968011', False), ('0123456789019', False), ('1234567890127', False), ) for t in test_data: print t == is_valid_barcode(t)
May 14, 2011
I recently made a new portfolio site for budding young product designer Emma Claire Stopford. Designed by the two of us and built by me all the in same day I'm happy with the result — especially given the speed we managed it in.
It's a simple 2 page site that uses jQuery to show and hide the products. All content is managed by Emma.
Was quite a fun little speed-project really!
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