[Python-announce] Brand new: Line Profiler GUI v0.1
Hi all, In the dark moments of code optimization, line_profiler from Robert Kern (now https://github.com/pyutils/line_profiler) helped me a lot. To ease the usage of this tool I created a GUI, namely "Line Profiler GUI". The installation is just a pip command away (choose your favorite python Qt binding): $ pip install line-profiler-gui[PySide2] $ pip install line-profiler-gui[PyQt5] The code is available on Github: https://github.com/Nodd/lineprofilergui Happy optimization! Joseph ___ Python-announce-list mailing list -- python-announce-list@python.org To unsubscribe send an email to python-announce-list-le...@python.org https://mail.python.org/mailman3/lists/python-announce-list.python.org/ Member address: arch...@mail-archive.com
[issue33646] os.fspath() bypasses __fspath__ for str subclasses
New submission from Joseph Martinot-Lagarde <contreba...@gmail.com>:
os.fspath() returns its argument if it is a str. That means that it bypasses
__fspath__ for str subclasses.
This is the case for the library path.py for example.
This is a corner case that was discovered while trying to fix
https://github.com/matplotlib/matplotlib/issues/11306
Minimal example:
```
import os
class MyPath(str):
def __fspath__(self):
print("Returns a pure string")
return str(self)
os.fspath(MyPath()) # Prints nothing
```
--
components: Library (Lib)
messages: 317666
nosy: contrebasse
priority: normal
severity: normal
status: open
title: os.fspath() bypasses __fspath__ for str subclasses
type: behavior
versions: Python 3.6
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Re: Python vs C++
Le 23/08/2014 16:21, Chris Angelico a écrit : On Sun, Aug 24, 2014 at 12:02 AM, Ian Kelly ian.g.ke...@gmail.com wrote: I don't know how fast lilypond is, but perhaps one could write an editor that wraps lilypond and invokes it in realtime to show the output in an adjacent panel, perhaps with a brief delay when the user stops typing. You theoretically could, but it'd be a bit awkward in places. It's not hard for a small textual change to result in a large visual change (eg if you use relative notes and add/remove an octave shift - it'll shift every subsequent note in the staff, which might mean more/less ledger lines needed, which will affect how much vertical space the staff needs, which will affect pagination...), so it'd often make for rather nasty flicker. Better to keep it explicit. ChrisA Frescobaldi (http://www.frescobaldi.org/) works exactly like this. It's like a latex IDE but for lilypond. It's quite powerfull and multiplatform. I use it exclusively now, it's way better that the bash script I used before that more or less rebuild the files when changed. This way you get the power of plain text and you have an almost instantaneous snapshot of the end result. -- https://mail.python.org/mailman/listinfo/python-list
Re: Python vs C++
Le 22/08/2014 02:26, Chris Angelico a écrit : On Fri, Aug 22, 2014 at 4:05 AM, Joseph Martinot-Lagarde joseph.martinot-laga...@m4x.org wrote: For information, Cython works with C++ now: http://docs.cython.org/src/userguide/wrapping_CPlusPlus.html. Now isn't that cool! Every time Cython gets discussed, I get a renewed desire to learn it. Trouble is, I don't have any project that calls for it - there's nothing I'm desperately wanting to do that involves both Python and C/C++. Anyone got any suggestions? :) ChrisA A python API for OpenSceneGraph ? I wouldn't use cython for this, though... -- https://mail.python.org/mailman/listinfo/python-list
Re: Python vs C++
Le 21/08/2014 15:40, Chris Angelico a écrit : On Thu, Aug 21, 2014 at 10:54 PM, David Palao dpalao.pyt...@gmail.com wrote: Why to use C++ instead of python? This is, perhaps, a bit off-topic, but I really want to know the thoughts of experienced python programmers on it. No, it's a fair question. Why are we all here? The fact is, there's not a huge amount of reason left. If you're linking against a C++ API, you may find it easiest to do the whole program in C++, rather than use something like Cython (which, as far as I'm aware, is C-only) or write a two-part project. And obviously if you have an existing C++ codebase, then porting it has costs, and maintaining it is probably better. But for the most part, I would strongly recommend starting a project in a high level language like Python unless there's a really compelling reason to do otherwise. C++ has, of late, been growing a number of features that belong in higher level languages; but if you want those sorts of features, why not just grab Python or Pike or something and save yourself the trouble? For information, Cython works with C++ now: http://docs.cython.org/src/userguide/wrapping_CPlusPlus.html. Joseph -- https://mail.python.org/mailman/listinfo/python-list
Re: IDE for python
Le 28/05/2014 13:31, Sameer Rathoud a écrit : I was searching for spyder, but didn't got any helpful installable. What problem did you encounter while trying to install spyder ? Spyder is oriented towards scientific applications, but can be used as a general python IDE. I use it for GUI development too. --- Ce courrier électronique ne contient aucun virus ou logiciel malveillant parce que la protection avast! Antivirus est active. http://www.avast.com -- https://mail.python.org/mailman/listinfo/python-list
Re: How can this assert() ever trigger?
Le 13/05/2014 11:56, Albert van der Horst a écrit : In article mailman.9917.1399914607.18130.python-l...@python.org, Joseph Martinot-Lagarde joseph.martinot-laga...@m4x.org wrote: Le 10/05/2014 17:24, Albert van der Horst a écrit : I have the following code for calculating the determinant of a matrix. It works inasfar that it gives the same result as an octave program on a same matrix. / def determinant( mat ): .. result = lastr[jx] assert(result0.) ... assert(result0.) nom *= result # Compenstate for multiplying a row. ... assert(nom0.) .. /- Now on some matrices the assert triggers, meaning that nom is zero. How can that ever happen? mon start out as 1. and gets multiplied with a number that is asserted to be not zero. Any hints appreciated. Groetjes Albert I know it's not the question, but if you want a replacement for octave did you try numpy (and scipy) ? The determinant would be computer faster and with less memory than with your function. I'm using several programming languages in a mix to solve Euler problems. This is about learning how octave compares to python for a certain kind of problem as anything. The determinant program I had lying around, but it was infinite precision with integer only arithmetic. Then I made a simple modification and got mad because I didn't understand why it didn't work. I have used numpy and its det before, but I find it difficult to remember how to create a matrix in numpy. This is the kind of thing that is hard to find in the docs. Now I looked it up in my old programs: you start a matrix with the zeroes() function. I expect the built in determinant of octave to be on a par with corresponding python libraries. --- Groetjes Albert You can use numpy.zeros(), but you can also use the same list of lists that you use for your problem. Transform a list of lists into a numpy array: np.asarray([[1, 2],[3, 4]]) array([[1, 2], [3, 4]]) Use a numpy function directly on a list of lists (works for must numpy functions): np.linalg.det([[1, 2],[3, 4]]) -2.0004 More info on array creation: http://wiki.scipy.org/Tentative_NumPy_Tutorial#head-d3f8e5fe9b903f3c3b2a5c0dfceb60d71602cf93 --- Ce courrier électronique ne contient aucun virus ou logiciel malveillant parce que la protection avast! Antivirus est active. http://www.avast.com -- https://mail.python.org/mailman/listinfo/python-list
Re: NumPy, SciPy, Python 3X Installation/compatibility issues
Le 10/05/2014 19:07, esaw...@gmail.com a écrit : Hi All-- Let me state at the start that I am new to Python. I am moving away from Fortran and Matlab to Python and I use all different types of numerical and statistical recipes in my work. I have been reading about NumPy and SciPy and could not find any definitive answers to my questions, below. I had run into many mostly installation problems that I could never get NumPy or SciPy to work with Python 3.3 or newer. I am using Windows7 64 bit OS. A few questions: 1. What are the latest versions of NumPy and SciPy that are compatible with Python 3.3 or newer and Windows7 64 bit? 2. What is the best source to download and install them on my computer? 3. Are they all installable on my OS w/o any major problems/addition? 4. In the long run, would it be better to use UNIX instead of Windows, if I were to use Python for all of my research? Thanks in advance. EK Building the scientific libraries on windows is very tricky because you need a compatible C and Fortran compiler, as well as some libraries. The usual and recommended route is to use python distributions where the most used libraries are installed. You can still use pip to install additionnal packages. You have a list over here: http://www.scipy.org/install.html --- Ce courrier électronique ne contient aucun virus ou logiciel malveillant parce que la protection avast! Antivirus est active. http://www.avast.com -- https://mail.python.org/mailman/listinfo/python-list
Re: How can this assert() ever trigger?
Le 10/05/2014 17:24, Albert van der Horst a écrit : I have the following code for calculating the determinant of a matrix. It works inasfar that it gives the same result as an octave program on a same matrix. / def determinant( mat ): ''' Return the determinant of the n by n matrix mat i row j column Destroys mat ! ''' #print getting determinat of, mat n=len(mat) nom = 1. if n == 1: return mat[0][0] lastr = mat.pop() jx=-1 for j in xrange(n): if lastr[j]: jx=j break if jx==-1: return 0. result = lastr[jx] assert(result0.) # Make column jx zero by subtracting a multiple of the last row. for i in xrange(n-1): pivot = mat[i][jx] if 0. == pivot: continue assert(result0.) nom *= result # Compenstate for multiplying a row. for j in xrange(n): mat[i][j] *= result for j in xrange(n): mat[i][j] -= pivot*lastr[j] # Remove colunm jx for i in xrange(n-1): x= mat[i].pop(jx) assert( x==0 ) if (n-1+jx)%20: result = -result det = determinant( mat ) assert(nom0.) return result*det/nom /- Now on some matrices the assert triggers, meaning that nom is zero. How can that ever happen? mon start out as 1. and gets multiplied with a number that is asserted to be not zero. Any hints appreciated. Groetjes Albert I know it's not the question, but if you want a replacement for octave did you try numpy (and scipy) ? The determinant would be computer faster and with less memory than with your function. --- Ce courrier électronique ne contient aucun virus ou logiciel malveillant parce que la protection avast! Antivirus est active. http://www.avast.com -- https://mail.python.org/mailman/listinfo/python-list
Re: The “does Python have variables?” debate
Le 08/05/2014 02:35, Ben Finney a écrit : Marko Rauhamaa ma...@pacujo.net writes: Ben Finney b...@benfinney.id.au: That's why I always try to say “Python doesn't have variables the way you might know from many other languages”, Please elaborate. To me, Python variables are like variables in all programming languages I know. Many established and still-popular languages have the following behaviour:: # pseudocode foo = [1, 2, 3] bar = foo # bar gets the value [1, 2, 3] assert foo == bar # succeeds foo[1] = spam# foo is now == [1, spam, 3] assert foo == bar # FAILS, ‘bar’ == [1, 2, 3] This is because such languages treat each variable as “containing” a value. Assignment puts another copy of the value in the variable, after which those two values have a distinct history. What happens to one value does not affect the other. Python, on the other hand, has this behaviour:: foo = [1, 2, 3] bar = foo # ‘bar’ binds to the value ‘[1, 2, 3]’ assert foo == bar # succeeds foo[1] = spam# ‘foo’ *and* ‘bar’ now == [1, spam, 3] assert foo == bar # succeeds, ‘bar’ is bound to ‘[1, spam, 3]’ The assignment statement in Python does not put a value in a container, the way it does for variables in many popular languages. Instead, assignment binds the left-hand-side reference (in these examples, names) to the right-hand-side value. Both remain references to the same value until the binding changes to some other value. So Python doesn't have variables in the way programmers coming from many other languages expect. Instead, it has references bound to values. For me, names bound to values is the same concept as pointer pointing to memory. bar = foo copies the pointer and not the underlying memory. This is not a foreign concept to C programmers. --- Ce courrier électronique ne contient aucun virus ou logiciel malveillant parce que la protection avast! Antivirus est active. http://www.avast.com -- https://mail.python.org/mailman/listinfo/python-list
