Is it possible to perform multi-linear regression in Python using NumPy?
The documentation here suggests that it is, but I cannot find any more details on the topic.
In Python I have a list of n lists, each with a variable number of elements. How can I create a single list containing all the possible permutations:
For example
[ [ a, b, c], [d], [e, f] ]
I want
[ [a, d, e] , [a, d, f], [b, d, e], [b, d, f], [c, d, e], [c, d, f] ]
Note I don't know n in advance. I thought itertools.product would be the right approach but it requires me to know the number of arguments in advance
Hi,
I need a memory efficient int-int dict in Python that would support the following operations in O(log n) time:
d[k] = v # replace if present
v = d[k] # None or a negative number if not present
I need to hold ~250M pairs, so it really has to be tight.
Do you happen to know a suitable implementation (Python 2.7)?
EDIT Removed impossible requirement and other nonsense. Thanks, Craig and Kylotan!
To rephrase. Here's a trivial int-int dictionary with 1M pairs:
>>> import random, sys
>>> from guppy import hpy
>>> h = hpy()
>>> h.setrelheap()
>>> d = {}
>>> for _ in xrange(1000000):
... d[random.randint(0, sys.maxint)] = random.randint(0, sys.maxint)
...
>>> h.heap()
Partition of a set of 1999530 objects. Total size = 49161112 bytes.
Index Count % Size % Cumulative % Kind (class / dict of class)
0 1 0 25165960 51 25165960 51 dict (no owner)
1 1999521 100 23994252 49 49160212 100 int
On average, a pair of integers uses 49 bytes.
Here's an array of 2M integers:
>>> import array, random, sys
>>> from guppy import hpy
>>> h = hpy()
>>> h.setrelheap()
>>> a = array.array('i')
>>> for _ in xrange(2000000):
... a.append(random.randint(0, sys.maxint))
...
>>> h.heap()
Partition of a set of 14 objects. Total size = 8001108 bytes.
Index Count % Size % Cumulative % Kind (class / dict of class)
0 1 7 8000028 100 8000028 100 array.array
On average, a pair of integers uses 8 bytes.
I accept that 8 bytes/pair in a dictionary is rather hard to achieve in general. Rephrased question: is there a memory-efficient implementation of int-int dictionary that uses considerably less than 49 bytes/pair?
First of all, I get the name of the current window
win32gui.GetWindowText(win32gui.GetForegroundWindow())
k, no problem with that...
But now, how can I make an if with the result for having an specific string on it...
For example, the result gave me
C:/Python26/
How can I make an True of False for the result containing the word, 'python' ?
I'm trying with re.search, but I'm not being able to make it do it
I'm looking for a way to prevent multiple hosts from issuing simultaneous commands to a Python XMLRPC listener. The listener is responsible for running scripts to perform tasks on that system that would fail if multiple users tried to issue these commands at the same time. Is there a way I can block all incoming requests until the single instance has completed?
I have some ctypes bindings, and for each body.New I should call body.Free. The library I'm binding doesn't have allocation routines insulated out from the rest of the code (they can be called about anywhere there), and to use couple of useful features I need to make cyclic references.
I think It'd solve if I'd find a reliable way to hook destructor to an object. (weakrefs would help if they'd give me the callback just before the data is dropped.
So obviously this code megafails when I put in velocity_func:
class Body(object):
def __init__(self, mass, inertia):
self._body = body.New(mass, inertia)
def __del__(self):
print '__del__ %r' % self
if body:
body.Free(self._body)
...
def set_velocity_func(self, func):
self._body.contents.velocity_func = ctypes_wrapping(func)
I also tried to solve it through weakrefs, with those the things seem getting just worse, just only largely more unpredictable.
Even if I don't put in the velocity_func, there will appear cycles at least then when I do this:
class Toy(object):
def __init__(self, body):
self.body.owner = self
...
def collision(a, b, contacts):
whatever(a.body.owner)
So how to make sure Structures will get garbage collected, even if they are allocated/freed by the shared library?
There's repository if you are interested about more details: http://bitbucket.org/cheery/ctypes-chipmunk/
I am using python lxml library to parse html pages:
import lxml.html
# this might run indefinitely
page = lxml.html.parse('http://stackoverflow.com/')
Is there any way to set timeout for parsing?
Hi folks,
I'm using the timeout parameter within the urllib2's urlopen.
urllib2.urlopen('http://www.example.org', timeout=1)
How do I tell Python that if the timeout expires a custom error should be raised?
Any ideas?
Is there any python module to convert PDF files into text? I tried one piece of code found in Activestate which uses pypdf but the text generated had no space between and was of no use.
I have a list in python ('A','B','C','D','E'), how do I get which item is under a particular index number?
Example:
Say it was given 0, it would return A.
Given 2, it would return C.
Given 4, it would return E.
There is function in python called eval that takes string input and evaluates it.
>>> x = 1
>>> print eval('x+1')
2
>>> print eval('12 + 32')
44
>>>
What is Haskell equivalent of eval function?
I have 4 reasonably complex r scripts that are used to manipulate csv and xml files. These were created by another department where they work exclusively in r.
My understanding is that while r is very fast when dealing with data, it's not really optimised for file manipulation. Can I expect to get significant speed increases by converting these scripts to python? Or is this something of a waste of time?
Is there a way to get functionality similar to mkdir -p on the shell... from within python. I am looking for a solution other than a system call. I am sure the code is less than 20 lines... really I am wondering if someone has already written it?
I've a python script that gives me 2 lists and another who is the reference(the time).
How can I create a graphic with the representation of my first list by the time. And same question for the second list. I need them on the same graphic.
list1 [12, 15, 17, 19]
list2 [34, 78, 54, 67]
list3 [10, 20, 30, 40] (time in minutes)
How can I create a graphic in png format with these lists?
Thanks
Hi,
I have a script where I launch with popen a shell command.
The problem is that the script don't wait that popen command is finished and go forward.
om_points = os.popen(command, "w")
.....
How can I tell to my python script to wait until the shell command has finished?
Thanks.
hi, i am siva this is frist time taken the python programming language i have a small problem please help me the question is **Write two functions, called countSubStringMatch and countSubStringMatchRecursive that take two arguments, a key string and a target string. These functions iteratively and recursively count the number of instances of the key in the target string. You should complete definitions for
def countSubStringMatch(target,key):
and
def countSubStringMatchRecursive (target, key):
**
I use the following method to break the double loop in Python.
for word1 in buf1:
find = False
for word2 in buf2:
...
if res == res1:
print "BINGO " + word1 + ":" + word2
find = True
if find:
break
Is there better way to break the double loop?
I'm looking for up-to-date documentation and tutorials on creating Python bindings for gobjects. Everything I can find on the web is either incomplete or out of date.
Ignoring all the characteristics of each languages and focusing SOLELY on speed, which language is better performance-wise?
You'd think this would be a rather simple question to answer, but I haven't found a decent one.
I'm aware that some types of operations may be faster with python, and vice-versa, but I cannot find any detailed information on this. Can anyone shed some light on the performance differences?
Is there any free Python to C translator? for example capable to translate such lib as lib for Fast content-aware image resizing (which already depends on some C libs) to C classes and files?
What are my best options for creating a financial open-high-low-close (OHLC) chart in a high level language like Ruby or Python? While there seem to be a lot of options for graphing, I haven't seen any gems or eggs with this kind of chart.
http://en.wikipedia.org/wiki/Open-high-low-close_chart (but I don't need the moving average or Bollinger bands)
JFreeChart can do this in Java, but I'd like to make my codebase as small and simple as possible.
Thanks!