performance of tight loop

[Paul Rubin]

gry <georgeryoung at gmail.com> writes:
...
>     rest =  ['%d' % randint(1, mx) for i in range(wd - 1)]
>         for i in range(i,i+rows): ...

One thing that immediately comes to mind is use xrange instead of range.

Also, instead of 
    first = ['%d' % i]
    rest =  ['%d' % randint(1, mx) for i in range(wd - 1)]
    return first + rest

you might save some copying with:

    rest =  ['%d' % randint(1, mx) for i in xrange(wd)]
    rest[0] = '%d'%i
    return rest

That's uglier than the old-fashioned
  rest = ['%d'%i]
  for i in xrange(wd-1):
     rest.append('%d' % randint(1, mx))

I think a generator would be cleanest, but maybe slowest:

   def row(i, wd, mx):
      yield '%d' % i
      for j in xrange(wd-1):
          yield ('%d' % randint(1, mx))