File to dict

[Neil Cerutti]

Re: File to dict

On 2007-12-07, Bruno Desthuilliers <bruno.42.desth uilliers@wtf.we bsiteburo.oops. comwrote:

mrkafk@gmail.co m a écrit :

>>

>>The csv module is your friend.

>>
>(slapping forehead) why the Holy Grail didn't I think about this?

>
If that can make you feel better, a few years ago, I spent two
days writing my own (SquaredWheel(t m) of course) csv
reader/writer... before realizing there was such a thing as the
csv module :-/
>
Should have known better...

But probably it has made you a better person. ;)

--
Neil Cerutti

[Duncan Booth]

Re: File to dict

Neil Cerutti <horpner@yahoo. comwrote:

On 2007-12-07, Duncan Booth <duncan.booth@i nvalid.invalidw rote:

>from __future__ import with_statement
>>
>def loaddomainowner s(domain):
> with open('/etc/virtual/domainowners',' r') as infile:

>
I've been thinking I have to use contextlib.clos ing for
auto-closing files. Is that not so?
>

That is not so.

Python 2.5.1 (r251:54863, Apr 18 2007, 08:51:08) [MSC v.1310 32 bit
(Intel)] on win32
Type "help", "copyright" , "credits" or "license" for more information.

>>from __future__ import with_statement
>>with open('diffs.txt ') as f:

.... print len(list(f))
....
40

>>f

<closed file 'diffs.txt', mode 'r' at 0x00AA0698>

>>>

[Glauco]

Re: File to dict

mrkafk@gmail.co m ha scritto:

Hello everyone,
>
I have written this small utility function for transforming legacy
file to Python dict:
>
>
def lookupdmo(domai n):
lines = open('/etc/virtual/domainowners',' r').readlines()
lines = [ [y.lstrip().rstr ip() for y in x.split(':')] for x in
lines]
lines = [ x for x in lines if len(x) == 2 ]
d = dict()
for line in lines:
d[line[0]]=line[1]
return d[domain]
>

cache = None

def lookup( domain ):
if not cache:
cache = dict( [map( lambda x: x.strip(), x.split(':')) for x in
open('/etc/virtual/domainowners',' r').readlines()])
return cache.get(domai n)





Glauco

[Neil Cerutti]

Re: File to dict

On 2007-12-07, Duncan Booth <duncan.booth@i nvalid.invalidw rote:

Neil Cerutti <horpner@yahoo. comwrote:
>

>On 2007-12-07, Duncan Booth <duncan.booth@i nvalid.invalidw rote:

>>from __future__ import with_statement
>>>
>>def loaddomainowner s(domain):
>> with open('/etc/virtual/domainowners',' r') as infile:

>>
>I've been thinking I have to use contextlib.clos ing for
>auto-closing files. Is that not so?
>>

That is not so.
>
Python 2.5.1 (r251:54863, Apr 18 2007, 08:51:08) [MSC v.1310 32 bit
(Intel)] on win32
Type "help", "copyright" , "credits" or "license" for more information.

>>>from __future__ import with_statement
>>>with open('diffs.txt ') as f:

... print len(list(f))
...
40

>>>f

><closed file 'diffs.txt', mode 'r' at 0x00AA0698>

Thanks. After seeing your answer I managed to find what I'd
overlooked before, in the docs for file.close:

As of Python 2.5, you can avoid having to call this method
explicitly if you use the with statement. For example, the
following code will automatically close f when the with block
is exited:

from __future__ import with_statement

with open("hello.txt ") as f:
for line in f:
print line

--
Neil Cerutti

[david]

Re: File to dict

On Fri, 07 Dec 2007 16:46:56 +0100, Glauco wrote:

mrkafk@gmail.co m ha scritto:

>Hello everyone,
>>
>I have written this small utility function for transforming legacy file
>to Python dict:
>>
>>
>def lookupdmo(domai n):
> lines = open('/etc/virtual/domainowners',' r').readlines() lines
> = [ [y.lstrip().rstr ip() for y in x.split(':')] for x in
>lines]
> lines = [ x for x in lines if len(x) == 2 ] d = dict()
> for line in lines:
> d[line[0]]=line[1]
> return d[domain]
>>
>>

cache = None
>
def lookup( domain ):
if not cache:
cache = dict( [map( lambda x: x.strip(), x.split(':')) for x in
open('/etc/virtual/domainowners',' r').readlines()])
return cache.get(domai n)
>

>>lookup(1)

Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "<stdin>", line 2, in lookup
UnboundLocalErr or: local variable 'cache' referenced before assignment

You miss the:
def lookup(domain):
global cache
...

bye

[Glauco]

Re: File to dict

david ha scritto:

On Fri, 07 Dec 2007 16:46:56 +0100, Glauco wrote:
>

>mrkafk@gmail.co m ha scritto:

>>Hello everyone,
>>>
>>I have written this small utility function for transforming legacy file
>>to Python dict:
>>>
>>>
>>def lookupdmo(domai n):
>> lines = open('/etc/virtual/domainowners',' r').readlines() lines
>> = [ [y.lstrip().rstr ip() for y in x.split(':')] for x in
>>lines]
>> lines = [ x for x in lines if len(x) == 2 ] d = dict()
>> for line in lines:
>> d[line[0]]=line[1]
>> return d[domain]
>>>
>>>

>cache = None
>>
>def lookup( domain ):
> if not cache:
> cache = dict( [map( lambda x: x.strip(), x.split(':')) for x in
>open('/etc/virtual/domainowners',' r').readlines()])
> return cache.get(domai n)
>>

>

>>>lookup(1)

Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "<stdin>", line 2, in lookup
UnboundLocalErr or: local variable 'cache' referenced before assignment
>
You miss the:
def lookup(domain):
global cache
...
>
bye

yezzz!

you can use global or static


Gla

[mrkafk@gmail.com]

Re: File to dict



Glauco wrote:

cache = None
>
def lookup( domain ):
if not cache:
cache = dict( [map( lambda x: x.strip(), x.split(':')) for x in
open('/etc/virtual/domainowners',' r').readlines()])
return cache.get(domai n)

Neat solution! It just needs small correction for empty or badly
formed lines:

dict([map( lambda x: x.strip(), x.split(':')) for x in open('/etc/
virtual/domainowners',' r') if ':' in x])

[Jeremy C B Nicoll]

Re: File to dict

Chris <cwitts@gmail.c omwrote:

For the first one you are parsing the entire file everytime you want
to lookup just one domain...

Is the file sorted? If so wouldn't it be easier either to read the whole
thing and then binary-chop search it, or if the file is vast to use seek
creatively to binary chop it but only read particular records from disk?

(One could chop by using seek to locate to a particular byte location in the
file then read to end of that record then read the next complete record.)

If the file isn't sorted, then .... why not? Also if the file is vast
surely there's some or a lot of point in breaking it up into a group of
smaller files?

--
Jeremy C B Nicoll - my opinions are my own.