string stripping issues

[orangeDinosaur]

Hello,

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.

[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

[ianaré]

from the python manual:

strip( [chars])
The chars argument is not a prefix or suffix; rather, all combinations
of its values are stripped:

'www.example.com'.strip('cmowz.') 'example'

in your case since the letter 'H' is in your [chars] and the name
starts with an H it gets stripped, but with the second one the first
letter is a K so it stops there.
Maybe you can use:
a[31:] 'Hughes. John</FONT></TD>\r\n' b[31:] 'Kim, Dong-Hyun</FONT></TD>\r\n'

but maybe what you REALLY want is:
a[31:-14] 'Hughes. John' b[31:-14]

'Kim, Dong-Hyun'

[Ben Cartwright]

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!'

--Ben

[orangeDinosaur]

thanks!

[P Boy]

This seems like a web page parsing question. Another approach can be as
follows if you know the limiting token strings:

a.split(' <TD WIDTH=175><FONT
SIZE=2>')[1].split('</FONT></TD>\r\n')[0]

[Iain King]

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

[Larry Bates]

orangeDinosaur wrote:

Hello,

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.

Others have explained the exact problem, I'll make a suggestion.
Take a few minutes to look at BeautifulSoup. It parses HTML code
and allows for extractions of data from strings like this in a
very easy to use way. If this is a one-off thing, don't bother.
If you do this commonly, BeautifulSoup is worth a little study.

-Larry Bates