"Klaus Neuner" <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]
> Hello,
>
> I need to gather information that is contained in various files.
>
> Like so:
>
> file1:
> =
> foo : 1 2
> bar : 2 4
> baz : 3
> =
>
> file2:
> =
> foo
Hello,
(Sorry for beginning a new thread. Google does not allow me to reply
to my own posting. And I cannot use a newsreader at the moment.)
Thanks to all who participated in the thread.
I tried the try- and the if-solution. The setdefault-solution didn't
work in my program.
With the try-soluti
Simon Brunning <[EMAIL PROTECTED]> writes:
> On Tue, 14 Dec 2004 10:40:56 -0500, Peter Hansen <[EMAIL PROTECTED]> wrote:
>> Keith Dart wrote:
>> > Sigh, this reminds me of a discussion I had at my work once... It seems
>> > to write optimal Python code one must understand various probabilites of
>
Klaus Neuner wrote:
Yet, I have got 43 such files. Together they are 4,1M
large. In the future, they will probably become much larger.
At the moment, the process takes several hours. As it is a process
that I have to run very often, I would like it to be faster.
Others have shown how you can m
Klaus Neuner wrote:
The straightforward way to solve this problem is to create a
dictionary. Like so:
[...]
a, b = get_information(line)
if a in dict.keys():
dict[a].append(b)
else:
dict[a] = [b]
So I timed the three suggestions with a few different datasets:
> cat builddict.py
def askpermi
On Tue, 14 Dec 2004 10:40:56 -0500, Peter Hansen <[EMAIL PROTECTED]> wrote:
> Keith Dart wrote:
> > Sigh, this reminds me of a discussion I had at my work once... It seems
> > to write optimal Python code one must understand various probabilites of
> > your data, and code according to the likely sc
Keith Dart wrote:
> Aye...
>
> the dict.keys() line creates a temporary list, and then the 'in' does a
> linear search of the list. Better would be:
>
> try:
> dict[a].append(b)
> except KeyError:
> dict[a] = [b]
>
> since you expect the key to be there most of the time, this method i
Keith Dart wrote:
Sigh, this reminds me of a discussion I had at my work once... It seems
to write optimal Python code one must understand various probabilites of
your data, and code according to the likely scenario.
And this is different from optimizing in *any* other language
in what way?
-Pet
Fredrik Lundh wrote:
...
if dct.has_key(a):
dct[a].append(b)
else:
dct[a] = [b]
the drawback here is that if the number of collisions are high, you end
up doing lots of extra dictionary lookups. in that case, there are better
ways to do this.
Sigh, this reminds me of a discussion I had at m
[Keith]
> Sigh, this reminds me of a discussion I had at my work once... It seems
> to write optimal Python code one must understand various probabilites of
> your data, and code according to the likely scenario. 8-)
s/Python //g
--
Richie Hindle
[EMAIL PROTECTED]
--
http://mail.python.org/
Keith Dart wrote:
>>> try:
>>> dict[a].append(b)
>>> except KeyError:
>>> dict[a] = [b]
the drawback here is that exceptions are relatively expensive; if the
number of collisions are small, you end up throwing and catching lots
of exceptions. in that case, there are better ways to do thi
Kent Johnson wrote:
Keith Dart wrote:
try:
dict[a].append(b)
except KeyError:
dict[a] = [b]
or my favorite Python shortcut:
dict.setdefault(a, []).append(b)
Kent
Hey, when did THAT get in there? ;-) That's nice. However, the
try..except block is a useful pattern for many similiar situ
Keith Dart wrote:
try:
dict[a].append(b)
except KeyError:
dict[a] = [b]
or my favorite Python shortcut:
dict.setdefault(a, []).append(b)
Kent
--
http://mail.python.org/mailman/listinfo/python-list
Hello,
I need to gather information that is contained in various files.
Like so:
file1:
=
foo : 1 2
bar : 2 4
baz : 3
=
file2:
=
foo : 5
bar : 6
baz : 7
=
file3:
=
foo : 4 18
bar : 8
===
Klaus Neuner wrote:
Hello,
I need to gather information that is contained in various files.
Like so:
file1:
=
foo : 1 2
bar : 2 4
baz : 3
=
file2:
=
foo : 5
bar : 6
baz : 7
=
file3:
=
foo : 4 18
bar
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