Refactor a buffered class...

[lh84777]

Hello,

i'm looking for this behaviour and i write a piece of code which works,
but it looks odd to me. can someone help me to refactor it ?

i would like to walk across a list of items by series of N (N=3 below)
of these. i had explicit mark of end of a sequence (here it is '.')
which may be any length and is composed of words.

for: s = "this . is a . test to . check if it . works . well . it looks
. like ."
the output should be (if grouping by 3) like:

=> this .
=> this . is a .
=> this . is a . test to .
=> is a . test to . check if it .
=> test to . check if it . works .
=> check if it . works . well .
=> works . well . it looks .
=> well . it looks . like .

my piece of code :

import sys

class MyBuffer:
def __init__(self):
self.acc = []
self.sentries = [0, ]
def append(self, item):
self.acc.append(item)
def addSentry(self):
self.sentries.append(len(self.acc))
print >> sys.stderr, "\t", self.sentries
def checkSentry(self, size, keepFirst):
n = len(self.sentries) - 1
if keepFirst and n < size:
return self.acc
if n % size == 0:
result = self.acc
first = self.sentries[1]
self.acc = self.acc[first:]
self.sentries = [x - first for x in self.sentries]
self.sentries.pop(0)
return result

s = "this . is a . test to . check if it . works . well . it looks .
like ."
l = s.split()
print l

mb = MyBuffer()
n = 0
for x in l:
mb.append(x)
if x == '.':
# end of something
print "+", n
n += 1
mb.addSentry()
current = mb.checkSentry(3, True) # GROUPING BY 3
if current:
print "=>", current

-- 
http://mail.python.org/mailman/listinfo/python-list

Re: Refactor a buffered class...

[lh84777]

Michael Spencer a écrit :

> If you just need to 'walk across a list of items', then your buffer class and
> helper function seem unnecessary complex.  A generator would do the trick,
> something like:

actually for the example i have used only one sentry condition by they
are more numerous and complex, also i need to work on a huge amount on
data (each word are a line with many features readed from a file)

but generators are interesting stuff that i'm going to look closer.

thanks.

-- 
http://mail.python.org/mailman/listinfo/python-list

Re: Refactor a buffered class...

[lh84777]

Here is another version,

class ChunkeredBuffer:
def __init__(self):
self.buffer = []
self.sentries = []
def append(self, item):
self.buffer.append(item)
def chunk(self, chunkSize, keepFirst = False):
self.sentries.append(len(self.buffer))
forget = self.sentries[:-chunkSize]
if not keepFirst and len(self.sentries) < chunkSize:
return
if forget != []:
last = forget[-1]
self.buffer = self.buffer[last:]
self.sentries = [x - last for x in self.sentries[1:]]
print >> sys.stderr, self.sentries, len(self.sentries), forget
return self.buffer

but i was wondering how i could add, the last items if needed:

it looks . like .
like .

to the previous:

this .
this . is a .
this . is a . test to .
is a . test to . check if it .
test to . check if it . works .
check if it . works . well .
works . well . it looks like .

to have:

this .
this . is a .
this . is a . test to .
is a . test to . check if it .
test to . check if it . works .
check if it . works . well .
works . well . it looks like .
it looks . like .
like .

-- 
http://mail.python.org/mailman/listinfo/python-list

Re: Refactor a buffered class...

[lh84777]

oops

> to have:
>
> this .
> this . is a .
> this . is a . test to .
> is a . test to . check if it .
> test to . check if it . works .
> check if it . works . well .
> works . well . it looks like .
well . it looks like .
it looks like .

-- 
http://mail.python.org/mailman/listinfo/python-list

Re: Refactor a buffered class...

[lh84777]

thanks a lot to all, i help me to learn a lot !

(i finally use the generator trick, it is great...)

best regards.

-- 
http://mail.python.org/mailman/listinfo/python-list