Roy SmithWe already have a perfectly good syntax for entering octal
and hex integers,
There is this syntax:
1536 == int(600, 16)
that accepts strings only, up to a base of 36.
There are the hex() and oct() functions.
There is the %x and %o sintax, that isn't easy to remember.
There are the 0x600
The Digital Mars D compiler is a kind of improved c++, it contains a
foreach statement:
http://www.digitalmars.com/d/statement.html#foreach
Usage example:
foreach(int i, inout int p; v1) p = i;
Is equal to Python:
for i in xrange(len(v)): v[i] = i
That is: v1 = range(len(v1))
(Some people use
Thank you Bengt Richter and Sybren Stuvel for your comments, my little
procedure can be improved a bit in many ways, it was just a first
quickly written version (but it can be enough for a basic usage).
Bengt Richter:
good way to prepare for split
Maybe there is a better way, that is putting in
Tom Anderson:
And we're halfway to looking like perl already! Perhaps a more pythonic
thing would be to define a then operator:
all_lines = file1 then file2 then file3
Or a chain one:
all_lines = file1 chain file2 chain file3
Bearophile
--
This can be faster, it avoids doing the same things more times:
from string import maketrans, ascii_lowercase, ascii_uppercase
def create_words(afile):
stripper = '[,;{}_?!():[]\.=+-*\t\n\r^%0123456789/
mapper = maketrans(stripper + ascii_uppercase,
*len(stripper)
Michael J. Fromberger:
I can send you
a Python implementation I wrote, if you like; but if you're interested
in better understanding how the transform works, I would recommend you
try writing your own implementation.
I'd like to see it, if you want you can put it somewhere or send it
Grant Edwards wrote:
May God save us from professional looking web sites.
I like the Python web site. It's simple, easy to read, and easy to
use.
I strongly agree with you, the web is full of web sites that are nice
looking but have microscopic fixed fonts (against the very spirit of
Html),
CppNewBand maybe a readable default font is in order.
That font looks fine to me, maybe there's a problem in the default font
of your browser, you can probably fix your problem...
Bye,
bearophile
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# This can be a solution:
from operator import itemgetter
seq1a = ([2] * 4) + ([1] * 4)
seq2a = [complex(3-el,7-el) for el in range(1, 9)]
assert len(seq1a) == len(seq2a)
print seq1a, seq2a, \n
mix = zip(seq1a, seq2a)
# mix.sort() # Not possible
mix.sort(key=itemgetter(0))
# If you need tuples
This is a possible solution, using exceptions:
fileName = data
out = file(fileName + _filt.txt, w)
for line in file(fileName + .txt):
try:
nline = float(line)
except ValueError:
pass
else:
out.write(str(nline) + \n)
out.close()
If the file is small enough this
This can be of little interest of some people here, but I think it can
be interesting enough to justify a post.
An article on the Microsoft Command Shell:
http://arstechnica.com/guides/other/msh.ars
(Its syntax is rather Python-like, but Py syntax seems better to me,
even taking into account that
This post comes from a boring morning, if you are busy ignore this.
This post is only for relaxed people.
I've found this page, Syntax Across Languages, it contains many
errors and omissions, but it's interesting.
http://merd.sourceforge.net/pixel/language-study/syntax-across-languages.html
Thank you for the comments, Fredrik Lundh.
(that's (mostly) CPython-dependent, and should be avoided)
Then a non CPython-dependent way of doing it can be even more useful.
sure looks like four possible outcomes.
Right (but to me four explicit answers seem better than three answers
and an
Thank you Fredrik Lundh for showing everybody that indeed lot of people
feel the need of such function in Python too.
to create a generic version, you have to decide which sequences to treat like
sequences
In my version I give the function some parameter(s) to define what I
want to flatten.
Questo non e' sufficiente, ma puo' essere un punto di partenza:
http://www.pycode.com/modules/?id=2tab=download
Bearophile
--
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Thank you for all the answers, some people have already answered for me
about most details I don't agree :-)
Mike MeyerRexx has a global control that lets you set the number of
digits to be considered significant in doing an FP equality test.
Mathematica too, I think.
Tom AndersonThere are all
Erik Max Francis:
result = [sqrt(x**2 + y**2) for x, y in zip(xs, ys)]
Another possibility:
from math import hypot
result = [hypot(*xy) for xy in zip(xs, ys)]
Or better:
from math import hypot
result = map(hypot, xs, ys)
bearophile
--
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Sometimes I suggest to add things to the language (like adding some set
methods to dicts), but I've seen that I tend to forget the meaning of
six set/frozenset operators:
s t s = t
s | t s |= t
s ^ t s ^= t
My suggestion is to remove them, and keep them only as explicit
non-operator versions
Thank you George Sakkis for your fast and accurate answer. In my life I
am encountering lot of graph-based solutions to my problems. I'll try
to implement your solution as soon as possible.
Fredrik Lundhworking on a Python to C/C++ translator without knowing
what kind of optimizations a C/C++
This isn't code of mine, it's probably from the cookbook, maybe with
little changes:
| def addMethod(object, method, name=None):
| if name is None: name = method.func_name
| class newclass(object.__class__):
| pass
| setattr(newclass, name, method)
| object.__class__ =
The current version of ShedSkin (http://shedskin.sourceforge.net/
experimental Python to C++ compiler) is rather alpha, and the
development work is focused on debugging and implementing some more
basic Python functionality. But hopefully in future versions more work
will be spent to make the
It doesn't work yet, to me...
bearophile
--
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Nufox seems a really interesting thing (probably it can even be used to
design GUIs for local desktop apps), but the site seems down at the
moment.
Bye,
bearophile
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On Slashdot there is a discussion about the future C#3.0:
http://developers.slashdot.org/developers/05/09/18/0545217.shtml?tid=109tid=8
http://msdn.microsoft.com/vcsharp/future/
There are many differences, but it looks a bit more like Python:
Uhm, if the file is clean you can use something like this:
data = \
200501221530
John
*** long string here ***
200504151625
Clyde
*** clyde's long string here ***
200503130935
Jeremy
*** jeremy string here
records = [rec.split(\n) for rec in data.split(\n\n)]
records.sort()
print records
Dennis Lee Bieber:
Yes, but only when ref-counts go to 0... it may be that this tight loop never
allowed stuff to go to 0 ref-counts. It definitely never returned control, so
besides eating memory that way, any events for the GUI framework were also not
being handled and had to be queued.
BearophileThis can be fixed with a different dictionary that doesn't
contain the leading 0s,
No other dict is necessary:
! _nibbles = {0:, 1:0001, 2:0010, 3:0011,
! 4:0100, 5:0101, 6:0110, 7:0111,
! 8:1000, 9:1001, A:1010, B:1011,
! C:1100, D:1101, E:1110,
Witn your suggestions and with some tests and work I've solved most of
the problems, thank you all for the comments.
Peter Hansen:
What did you expect to happen with the infinite loop inside dogo()?
I expected that the same memory used by the b.config(command=...) can
be used by the successive
Hello, I have four things to ask or to suggest, sorry if they seem
basic or already discussed.
---
I am still ignorant about Tkinter. This little program, after pressing
the Go eats more and more RAM, is it normal? Can it be avoided? (In
normal programs this is isn't a real
I agree with Bryan Olson.
I think it's a kind of bug, and it has to be fixed, like few other
things.
But I understand that this change can give little problems to the
already written code...
Bye,
bearophile
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Two versions of mine, one of the fastest (not using Psyco) and one of
the shortest:
. from itertools import groupby
.
. def audioactiveFast(n):
. strl = {(1,1,1): 31, (1,1): 21, (1,): 11,
. (2,2,2): 32, (2,2): 22, (2,): 12,
. (3,3,3): 33, (3,3): 23, (3,): 13 }
.
Hello, I know this topic was discussed a *lot* in the past, sorry if it
bores you...
From the Daily Python-URL I've seen this interesting Floating Point
Benchmark:
http://www.fourmilab.ch/fourmilog/archives/2005-08/000567.html
This is the source pack:
http://www.fourmilab.ch/fbench/fbench.zip
This is the problem of finding the connected components inside an
interval graph. You can implement the algorithms yourself, of you can
use my graph data structure here:
http://sourceforge.net/projects/pynetwork/
The graph methods:
createIntervalgGraph
And:
connectedComponents
can probably solve
runes:
d = {}
for k in data:
try:
d[k] += 1
except:
d[k] = 1
for k,v in d.items():
if v == 1:
print k
For this problem, if duplicated keys are common enough, this version is
probably the faster.
With this *different* problem, it seems that sometimes
I've seen the benchmarks, they look quite interesting.
This project is probably a LOT of work; maybe people can tell us about
such efforts *before* doing so much work, so we can discuss it, and
avoid wasting time.
Maybe you can explain us why it is so fast, and/or maybe you can work
with the
Kay SchluehrWhat is wrong with the other librarys that they can't be
approved?
I presume there are so many kinds of graphs, that one data structure
doesn't fit all... On the other hand, I think that trying to design a
too much general data structure can have some drawbacks. I've tried a
Pynetwork is a graph library, my first SourceForge project:
http://sourceforge.net/projects/pynetwork/
It included tests, some demo, some premilinary docs, and some images.
You can see some screenshoots on the SourceForge page for them.
I know about 5-6 other graph libraries for Python, one even
Ville Vainio:
This is a good place to use 'get' method of dict:
frequency[word] = frequency.get(word,0) + 1
I think Kent Johnson is longer, but a bit faster...
Bye,
Bearophile
--
http://mail.python.org/mailman/listinfo/python-list
In my first post you can find two URLs with better flood filling
algorithms. You can also modify the easy recursive function, using a
list-based stack intead of recursive calls.
Bye,
Bearophile
--
http://mail.python.org/mailman/listinfo/python-list
Then you can probably use something like this:
. def boxesArea(m, foreground=1, background=0):
. maxr = len(m)
. maxc = len(m[0])
. newCol = 2
. oldCol = foreground
. for r,row in enumerate(m):
. for c,e in enumerate(row):
. if e == oldCol:
.
[EMAIL PROTECTED]:
hi Bearphile! That really gives me an idea.Thanks much for that. Yes
as
you said the algorithm reaches a maximium recursion depth for larger
sets i tried.
You can improve the little flood filling function, avoiding the bad
Python recursivity.
Do you see where I am heading
I hope this is what you need, sometimes understanding the question is
one of the hardest parts :-)
If you can use a graph data structure, you can create a graph, and then
you can find the lenght of all its connected components (indentations
reduced to 2 spaces):
. def mat2graph(g, m, good=None,
You can create your own Exception class, based on this recipe:
Thank you for your answer, the recipe you have suggested gives a very
big output, but it doesn't contain what I've asked for... :-) I was
asking to see that faulty method/function parameters (or the first line
of its docstring).
Hello, here I extend the idea of the smart help I've discussed
recently.
When I receive an error like:
TypeError: fun() takes exactly 2 arguments (1 given)
I'd also like to see that method/function parameters (or the first line
of its docstring).
From a discussion with gentle programmers in
Tim's solution is very nice, it comes from basic things often taught in
good computer science courses.
In Python when you have to do many (-1)**n you can do:
(1-2*(n%2))
This seems quite faster.
Bearophile
--
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There is a discussion about Python Moving into the Enterprise on
Slashdot:
http://it.slashdot.org/it/05/04/03/0715209.shtml?tid=156tid=8
Bearophile
--
http://mail.python.org/mailman/listinfo/python-list
Is that last idea so stupid? Still, I'd like to know if you know some
little Python search engines for such purpose.
Thank you,
Bearophile
--
http://mail.python.org/mailman/listinfo/python-list
Suggesting method names based on a wrong method name can be useful, but
I think the smart help can be improved: it can also be useful to have
a suggestion for method names on the basis on a short description (or
keywords) about what I want to do to/with the object. Maybe some people
here can give
The free wikipedia is adopting a standard pseudocode:
http://en.wikipedia.org/wiki/Wikipedia_talk:Wikicode/Specification
MShonle says something nice:
I support the idea of wikicode. Basically I think we should present
code in a Python-like language that doesn't carry so much baggage. For
example,
I have a class Surface with many methods. Working in the interactive
window I receive an error like this when I write the wrong method name:
table.addGlas()
Traceback (most recent call last):
File stdin, line 1, in ?
AttributeError: 'Surface' object has no attribute 'addGlas'
Is it possibile
Raymond HettingerWhen you're done, consider posting the result as an
ASPN cookbook recipe.
I still cannot write in the cookbook... I think I have problems with
the registration. So you can put it there...
I've found that difflib is good enough for the string matching. This
idea isn't fully mine,
Diez B. Roggischit will make an object return always _something_ - and
thus you don't catch misspellings in non-interactive
Uhm, I'm sorry, I don't understand you.
If you look at the code I've just posted, you can see that it still
raises AttributeError, the difference is just the error
It's still a toy, but it looks interesting. It converts in Python,
Lisp and Java, and the shown image looks like Python:
http://www.trnmag.com/Stories/2005/032305/Tool_turns_English_to_code_032305.html
Google cache for a draft about it:
R.H.:
The setdefault() method would continue to exist but
would likely not make it into Py3.0.
I agee to remove the setdefault.
I like the new count method, but I don't like the appendlist method,
because I think it's too much specilized.
I too use sets a lot; recently I've suggested to add a
Looking at all the hyperedges in the connected component is a big
waste... You can look at just the hyperedges that share one or more
nodes.
(Nodes are the original letters contained in the sets, and they must be
hashable).
If nodes aren't integers in [0, len(l)) then you can use this simpler
s1 = set(['a','b','c'])
s2 = set(['a','c'])
s3 = set(['a','d','e','f'])
s4 = set(['r','k','l'])
s5 = set(['r','k','l'])
ls = [s1,s2,s3,s4,s5]
result1 = [s1, s3, s5]
A result can contain s4 or s5 at random. This problem looks like the
one of searching the correct hyperedges for a hypergraph. s1-5
Michael Spencer's version is nice, this is a bit shortened version. The
main() isn't useful for this very short loop, and you can use shorter
variable names to make lines shorter (this code isn't much readable,
it's just for the Shootout, production quality code has probably to
be more readable.
Maybe this can help:
value = d.get('x', lambda: bigscaryfunction())
Bearophile
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This can be interesting:
http://science.slashdot.org/science/05/03/01/2340238.shtml
Bearophile
--
http://mail.python.org/mailman/listinfo/python-list
The use of frozenset can okay when sub-sequences are longer, but for
this problem it's slow, and anyway there are situations of repeated
data like this that have to be considered:
frozenset( ('a', 'a') )
==
frozenset(['a'])
For Py2.4 the faster and better solution seems Peter Otten one.
James
John Machin:
Perhaps I'm missing a posting of yours -- what are merge2 and merge4?
What is this random pairs test? What is xMax (nPairs isn't hard to
guess), and how are you generating your input data?
merge2 and this random pairs test comes from the post by Brian Beck.
merge4 is the first in my
Your two email addresses bouce emails back, so I post a shortened
version of my comment here.
I haven't installed:
PyOpenGL-2.0.2.01.py2.4-numpy23
glut-3.7.6
Therefore at the moment I cannot try your interesting code.
What's the speed of this Python code on your computer?
I'd like to see a
David Eppstein:
However it might be easier to treat the input pairs as the edges of a
graph and apply a depth-first-search based graph connected components
algorithm. || This would be O(n), though.
Is the DFS the best one here (instead of BFS)?
With the graph implementation that I've just
Bearophile:
I presume the complexity is O(n+a); n (the nodes)
is proportional to the number of pairs, and a
(the arcs) depends on the intricacy of the input pairs.
Opps... n (the number of nodes) is the number of different numbers
contained in the pairs :-]
Bearophile
--
John MachinFWIW, here's a brief UAT report:
Here is something else for you.
Note: for more correct comparisons, for the following tests I've
disabled the use of Psyco in Graph (usually enabled, if present).
This looks faster than merge2 for this (quite sparse) random pairs
test:
. import graph #
This is the first version of the graph module I was developing... In
the meantime I've seen that there are already lots of graph
implementations, even a compiled one:
ftp://xray.imsb.au.dk/pub/python/packages/Python2.1/RPMS/python-kjbuckets-2.2-7.i686.rpm
(This makes my work less important, but it
In Python there are so many ways to do things...
This looks like another one, I haven't tested it:
not False in imap(pred, iterable)
As usual tests are required to measure the faster one.
I agree with Roose, there are are some primitive operations (like
this, and flatten, partition, mass removal
Nick Coghlan wrote:
Anyway, check out AlternateLambdaSyntax on the python.org Wiki
It's an interesting page:
http://www.python.org/moin/AlternateLambdaSyntax
Some days ago I suggested something different: maybe def can become a
function, then it can work as lambda (and still as the old def) too.
This isn't a visualisation routine, but it contains some of them, and
with few mod you can adapt them for your needs:
http://gato.sourceforge.net/
Gato - the Graph Animation Toolbox - is a software which visualizes
algorithms on graphs.
Bearophile
--
Leif K-Brooks:
They look exactly the same speed-wise to me:
There's a little overhead, you can see it with a bigger test:
.from time import clock
.n = 1*10**6
.
.t1 = clock()
.d = set()
.for i in xrange(n):
. d.add(i)
.t2 = clock()
.for i in xrange(n):
. d.remove(i)
.t3 = clock()
.d =
r = {}
for x in a: if x not in b: r[x] = r[a]
for x in b: if x not in a: r[x] = r[b]
I know, this is wrong :-]
This looks better:
r = {}
for x in a: if x not in b: r[x] = a[x]
for x in b: if x not in a: r[x] = b[x]
Bearophile
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I'm frequently using Py2.4 sets, I find them quite useful, and I like
them, even if they seem a little slower than dicts. Sets also need the
same memory of dicts (can they be made to use less memory, not storing
values? Maybe this requires too much code rewriting).
I presume such sets are like
You are really gentle Raymond Hettinger, but surely I'm not asking
you/anyone to write some code just for me; I don't have real
applications, I'm just learning/playing.
Your words are quite good answers to most of my questions.
The only left small topic is about the group/set-like
Thank you to all the gentle people that has given me some comments, and
sorry for bothering you...
Doug Holton:
This will also likely never appear in Python.
I know, that's why I've defined it wild.
Also, you might request the NetLogo and StarLogo developers to support
Jython (in addition to
Adding Optional Static Typing to Python looks like a quite complex
thing, but useful too:
http://www.artima.com/weblogs/viewpost.jsp?thread=85551
I have just a couple of notes:
Boo (http://boo.codehaus.org/) is a different language, but I like its
as instead of : and -, to have:
def min(a as
Doug Holton:
And there are some disadvantages to doing it this way.
It means Python is more flexible to use than Boo,
I've just suggested the *syntax* that I like more.
Bye,
Bearophile
--
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(This is a repost from another python newsgroup).
While using some nested data structures, I've seen that I'd like to
have a function that tells me if a given data structure contains one or
more cyclic references (a way to recognise a cycle in a graph is to do
a depth-first search, marking
Leif K-Brooks:
http://python.org/doc/current/lib/module-pprint.html#l2h-749
Thank you very much, I see that the function is already there, even
with the same name :-)
I've seen that it doesn't work for all my tests, like this one with n =
3000:
from pprint import isrecursive
from time import
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