string stripping issues

Iain King iainking at gmail.com
Fri Mar 3 13:17:50 CET 2006


Ben Cartwright wrote:
> Ben Cartwright wrote:
> > 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!'
>
>
> Apologies, that should be:
>    >>> prefix = 'hello '
>    >>> bar = 'hello world!'
>    >>> if bar.startswith(prefix): bar = bar[len(prefix):]
>    ...
>    >>> bar
>    'world!'
>

or instead of:

 a.strip('    <TD WIDTH=175><FONT SIZE=2>')

use:

a.replace('    <TD WIDTH=175><FONT SIZE=2>','')

Iain




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