string stripping issues

[Ben Cartwright]

orangeDinosaur wrote:
> I am encountering a behavior I can think of reason for.  Sometimes,
> when I use the .strip module for strings, it takes away more than what
> I've specified.  For example:
>
> >>> a = '    <TD WIDTH=175><FONT SIZE=2>Hughes. John</FONT></TD>\r\n'
>
> >>> a.strip('    <TD WIDTH=175><FONT SIZE=2>')
>
> returns:
>
> 'ughes. John</FONT></TD>\r\n'
>
> However, if I take another string, for example:
>
> >>> b = '    <TD WIDTH=175><FONT SIZE=2>Kim, Dong-Hyun</FONT></TD>\r\n'
>
> >>> b.strip('    <TD WIDTH=175><FONT SIZE=2>')
>
> returns:
>
> 'Kim, Dong-Hyun</FONT></TD>\r\n'
>
> I don't understand why in one case it eats up the 'H' but in the next
> case it leaves the 'K' alone.


That method... I do not think it means what you think it means.  The
argument to str.strip is a *set* of characters, e.g.:

  >>> foo = 'abababaXabbaXabababbbb'
  >>> foo.strip('ab')
  'XabbaX'
  >>> foo.strip('aabababaab') # no difference!
  'XabbaX'

For more info, see the string method docs:
http://docs.python.org/lib/string-methods.html
To do what you're trying to do, try this:

  >>> prefix = 'hello '
  >>> bar = 'hello world!'
  >>> if bar.startswith(prefix): bar = bar[:len(prefix)]
  ...
  >>> bar
  'world!'

--Ben