On Friday 24 July 2009 17:07:30 Inky 788 wrote: > On Jul 23, 3:42 am, Hendrik van Rooyen <hend...@microcorp.co.za> > > wrote: 8<------------------------ > > Steven showed why you cannot have a mutable thing > > as a key in a dict. > > > > if you think it is contrived, then please consider how you would > > keep track of say the colour of a pixel on a screen at position > > (x,y) - this is about the simplest "natural" tuple format and > > example. > > My guess is that this is probably the way most people do it: > > ~~~~ > #!/usr/bin/env python > > import sys > import random > > if len( sys.argv ) != 3: > print "Please pass exactly 2 ints. Exiting." > sys.exit(1) > > NUM_COLUMNS = int( sys.argv[1] ) > NUM_ROWS = int( sys.argv[2] ) > > print "Making array of %s columns by %s rows." % (NUM_COLUMNS, > NUM_ROWS) > > def rand(): > return int( 255 * random.random()) > > def make_a_pixel(): > # red green blue > return [rand(), rand(), rand()] > > def make_a_row(num_columns): > temp_row = [] > for i in range(num_columns): > temp_row.append( make_a_pixel() ) > return temp_row > > def make_array_of_pixels(num_columns, num_rows): > rows = [] > for i in range(num_rows): > rows.append( make_a_row(num_columns) ) > return rows > > def show_pixels(pixel_array): > for row in pixel_array: > for pixel in row: > print pixel, ' ', > print > > > rows_of_pixels = make_array_of_pixels(NUM_COLUMNS, NUM_ROWS) > > show_pixels(rows_of_pixels) > ~~~~
Good grief! - Not a dictionary in sight! I had something in mind where point was an (x,y) tuple, and point_colours was a dict of possibly named points with a list of RGB values. (The colour can change, the point is fixed) If I were doing it your way, I would use the Array module's Array. But then, strictly speaking it would not be your way any more, would it? - Hendrik -- http://mail.python.org/mailman/listinfo/python-list
