the evolving FrankenString some search methods that enable
searching for the first occurrence in the string of any character out of
a set of characters given as a string, or any character not in such a
set. This has nothing to do yet with iterators and seeking/telling.
Just letting C do the while
Andreas Lobinger wrote:
t2 = f.find('2')+1
This is indeed faster than going through a string char by char. It doesn't
make for a nice character-based state machine, but of course it avoids
making Python objects for every character and uses the C implementation of
str for searching.
However,
hope you'll let us know how much faster your
final approach turns out to be.
I'm pretty convinced that implementing an algorithmically nice state
machine that goes through a string char by char won't get any faster than
using s[index] all the time unless I do a frankenstring in C. Failing
Aloha,
Thomas Lotze wrote:
A string, and a pointer on that string. If you give up the boundary
condition to tell backwards, you can start to eat up the string via f =
f[p:]. There was a performance difference with that, in fact it was faster
~4% on a python2.2.
When I tried it just now, it was
Thomas Lotze wrote:
And I wonder whether there shouldn't be str.findany and
str.iterfindany, which takes a sequence as an argument and returns the
next match on any element of it.
On second thought, that wouldn't gain much on a loop over finding each
sequence, but add more complexity than it
class FrankenString(StringIO):
lastidx = 0
atEnd = False
def __iter__(self):
while not self.atEnd:
char = self.read(1)
idx = self.tell()
if self.lastidx == idx
Here is a cStringIO based version:
class FrankenString:
def __init__(self,string=None):
self.str = StringIO(string)
self.atEnd = False
self.lastidx = 0
self.seek = self.str.seek
self.tell = self.str.tell
well that appears to have been munged up ...
that tell() belongs immediately after self.str. making it
self.str.tell()
class FrankenString:
def __init__(self,string=None):
self.str = StringIO(string)
self.atEnd = False
self.lastidx = 0
self.seek = self.str.seek
Thomas Lotze wrote:
It's definitely no help that file-like objects are iterable; I do want
to get a character, not a complete line, at a time.
Hi,
if i did understand what you mean, what about using mmap? Iterating over
characters in a file like this:
# -*- coding: iso-8859-1 -*-
import os
Thomas Lotze wrote:
I think I need an iterator over a string of characters pulling them out
one by one, like a usual iterator over a str does. At the same time the
thing should allow seeking and telling like a file-like object:
from StringIO import StringIO
class frankenstring(StringIO
which makes it nice to use, of course, and to most this will
be enough (and it is a lot indeed). But it loses the efficiency of
for c in asdf: do_something(c)
Actually, relying on string[index] behind the scenes is one of the ways
of implementing frankenstring I labelled clumsy in the original
Roland Heiber wrote:
class MmapWithSeekAndTell(object):
def __init__(self, m, size):
.. where m is a mmap-object and size the filesize ... sorry.
--
http://mail.python.org/mailman/listinfo/python-list
Aloha,
Thomas Lotze wrote:
I think I need an iterator over a string of characters pulling them out
one by one, like a usual iterator over a str does. At the same time the
thing should allow seeking and telling like a file-like object:
f = frankenstring(0123456789)
for c in f:
... print c
Thomas Lotze wrote:
Peter Otten wrote:
class frankenstring(StringIO):
... def next(self):
... c = self.read(1)
... if not c:
... raise StopIteration
... return c
Repeated read(1) on a file-like object is one of the ways
Hi,
I think I need an iterator over a string of characters pulling them out
one by one, like a usual iterator over a str does. At the same time the
thing should allow seeking and telling like a file-like object:
f = frankenstring(0123456789)
for c in f:
... print c
... if c == 2
Thomas Lotze wrote:
Hi,
I think I need an iterator over a string of characters pulling them out
one by one, like a usual iterator over a str does. At the same time the
thing should allow seeking and telling like a file-like object:
Okay, first off, this is never going to be *fast* compared
= frankenstring(0123456789)
for c in f:
... print c
... if c == 2:
... break
...
0
1
2
f.tell()
3L
f.seek(7)
for c in f:
... print c
...
7
8
9
It's definitely no help that file-like objects are iterable; I do want
to get a character, not a complete line, at a time.
I can think
jay graves wrote:
see StringIO or cStringIO in the standard library.
Just as with files, iterating over them returns whole lines, which is
unfortunately not what I want.
--
Thomas
--
http://mail.python.org/mailman/listinfo/python-list
Thomas Lotze wrote:
Hi,
I think I need an iterator over a string of characters pulling them out
one by one, like a usual iterator over a str does. At the same time the
thing should allow seeking and telling like a file-like object:
f = frankenstring(0123456789)
for c in f:
... print
Scott David Daniels wrote:
Now if you want to do it for a file, you could do:
for c in thefile.read():
The whole point of the exercise is that seeking on a file doesn't
influence iteration over its content. In the loop you suggest, I can
seek() on thefile to my heart's
On Wed, 13 Jul 2005 03:49:16 +0200, Thomas Lotze [EMAIL PROTECTED] wrote:
Scott David Daniels wrote:
Now if you want to do it for a file, you could do:
for c in thefile.read():
The whole point of the exercise is that seeking on a file doesn't
influence iteration over its
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