n00bie wants advice.

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  • bsagert@gmail.com
    #1

    n00bie wants advice.

    This simple script writes html color codes that can be viewed in a
    browser. I used short form hex codes (fff or 000, etc) and my list
    has only six hex numbers otherwise the results get rather large. I
    invite criticism as to whether my code is "pythonic". Are there other
    ways to generate the hex combos besides the nested "for" loops? Thanks
    in advance, Bill

    list = ['3','6','9','b' ,'d','f']

    s = '<html><head><s tyle>h1{margin: 0}</style></head><body>\n'

    for a in list:
    for b in list:
    for c in list:
    s += '<h1 style="backgrou nd:#'+ a + b + c +'">'+ a + b + c +'</h1>
    \n'

    s += '</body></html>'

    f = open('c:/x/test.htm', 'w')
    f.write(s)
    f.close()
    Tags: None
    • Marc 'BlackJack' Rintsch
      #2
      Re: n00bie wants advice.

      On Tue, 01 Jul 2008 23:25:53 -0700, bsagert wrote:
      This simple script writes html color codes that can be viewed in a
      browser. I used short form hex codes (fff or 000, etc) and my list
      has only six hex numbers otherwise the results get rather large. I
      invite criticism as to whether my code is "pythonic".
      You should not rebind the name `list` because it shadows the built in type
      of that name then. A more descriptive name would be nice anyway, i.e.
      `hex_digits`. And strings are iterable too, so it's a bit shorter and
      easier to type the digits a string.

      Repeatedly concatenating strings with ``+=`` might be performance problem.
      Python strings are immutable so this operation has to copy the involved
      and growing strings over and over again. Although the current CPython
      implementation can optimize here in some cases, the usual idiom is to use
      the `join()` method of strings to build a string from components in a list
      or iterable.

      Alternative implementation of your script:

      from __future__ import with_statement

      def main():
      html_template = ('<html><head>< style>h1{margin :0}</style></head><body>\n'
      '%s\n'
      '</body></html>\n')
      header_template = '<h1 style="backgrou nd:#%s">%s</h1>'
      hex_digits = '369bdf'
      colors = (a + b + c for a in hex_digits
      for b in hex_digits
      for c in hex_digits)
      html = html_template % '\n'.join(heade r_template % (c, c) for c in colors)
      with open('test.html ', 'w') as html_file:
      html_file.write (html)

      if __name__ == '__main__':
      main()

        Comment

        • A.T.Hofkamp
          #3
          Re: n00bie wants advice.

          On 2008-07-02, bsagert@gmail.c om <bsagert@gmail. comwrote:
          This simple script writes html color codes that can be viewed in a
          browser. I used short form hex codes (fff or 000, etc) and my list
          has only six hex numbers otherwise the results get rather large. I
          invite criticism as to whether my code is "pythonic". Are there other
          ways to generate the hex combos besides the nested "for" loops? Thanks
          in advance, Bill
          ok.

          variable names of 1 letter are very bad. Use more meaningful names like 'red'
          'green' etc.

          'list' is better, but also a name reserved by Python, so change that too.

          Indenting is normally 4 spaces in Python

          You can see "a + b +c" twice, compute it once, and assign it to a intermediate
          variable

          Use string formatting for better readability.

          In this case, you could also open the file earlier, and write all strings
          directly to file instead of first creating a string in memory

          Otherways of creating the colour code permutations: In this case, this is most
          Pythonic imho. You could write a list comprehension of even a recursive
          function, but I think it wouldn't increase readability.


          Albert

          list = ['3','6','9','b' ,'d','f']
          >
          s = '<html><head><s tyle>h1{margin: 0}</style></head><body>\n'
          >
          for a in list:
          for b in list:
          for c in list:
          s += '<h1 style="backgrou nd:#'+ a + b + c +'">'+ a + b + c +'</h1>
          \n'
          >
          s += '</body></html>'
          >
          f = open('c:/x/test.htm', 'w')
          f.write(s)
          f.close()

            Comment

            • oj
              #4
              Re: n00bie wants advice.

              On Jul 2, 7:25 am, bsag...@gmail.c om wrote:
              This simple script writes html color codes that can be viewed in a
              browser.  I used short form hex codes (fff or 000, etc) and my list
              has only six hex numbers otherwise the results get rather large. I
              invite criticism as to whether my code is "pythonic". Are there other
              ways to generate the hex combos besides the nested "for" loops? Thanks
              in advance, Bill
              >
              list = ['3','6','9','b' ,'d','f']
              >
              s = '<html><head><s tyle>h1{margin: 0}</style></head><body>\n'
              >
              for a in list:
                      for b in list:
                              for c in list:
                                      s += '<h1 style="backgrou nd:#'+ a + b + c +'">'+ a + b + c +'</h1>
              \n'
              >
              s += '</body></html>'
              >
              f = open('c:/x/test.htm', 'w')
              f.write(s)
              f.close()
              You could write the loop like this:

              for red, green, blue in [(r, g, b) for r in list for g in list for b
              in list]:
              s += blah blah blah

              but, arguably, that isn't easier to read or understand. It's a matter
              of taste, I guess.

              As has already been mentioned, list is not a good name, because it is
              already used.

              Also, personally, I find it easier to read strings that aren't
              constructed with concatenation, but using pythons string formatting
              gubbins:

              '<h1 style="backgrou nd: #%s%s%s">' % (red, green, blue)

              Again, I think this is mostly personal preference.

                Comment

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