Python is a dynamic, high-level language. Its design focuses on clear syntax, an intuitive approach to object-oriented programming, and making the right way to do things obvious. Python supports modules, exceptions, had an extensive standard module library. Python can also be embedded in other ...

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154 views

Best Practices For Temporary Scripts (Python)

I am running two separate programs which are similar enough that they share a lot of code. I run these programs often and after I evaluate the output. This is a very fluid process and everytime is ...
0
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1answer
132 views

Python case statement? [duplicate]

I made a simple Python script that takes user input in order to generate a series of mathematical responses. In one part I did this: while True: And iterated through the loop until I used an if ...
0
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2answers
131 views

How to route messages between clients using a central server in Python

I've got three Raspberry Pis sitting around. I want 2 of them to be able to chat while the 3rd routes the messages (acts as a server between them). The general flow of events should be something like ...
2
votes
1answer
231 views

How do you make decorators as powerful as macros?

Quick background: I am designing a Pythonic language that I want to be as powerful as Lisp while remaining easy to use. And by "powerful", I mean "flexible and expressive". I've just been introduced ...
0
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3answers
119 views

How to convert this recursive problem to iterative? Line Simplification algorithm fails to run due to Maximum Recursion Depth being hit

I am implementing the Douglas, Peucker's Line Simplification algorithm in Python. I started with this implementation. However, it fails to run in Python due to Maximum Recursion Depth being hit. How ...
0
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1answer
116 views

Running Python script in background on Mac

I have a Python script that counts the number of file in a folder, and if the number of files exceeds 10 then it creates a popup window to ask the user to clean up the folder (I use tkMessageBox). ...
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1answer
156 views

Is Lambda Still Supported In Python?

Only one or two years ago, I remember reading Python constructs that would be removed from Python -- reduce was one of them -- and other constructs that would be emphasized like comprehensions and ...
1
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1answer
151 views

Should I separate a web api from the webserver?

Lets say I'm building a site similar to this or Quora (or some arbitrary blog-like site). I need a real-time component that will be using web-sockets/long-polling to notify the user of new posts, ...
9
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5answers
959 views

Are there technical limitations or language features that prevent my Python script from being as fast as an equivalent C++ program?

I'm a long-time Python user. A few years ago, I started learning C++ to see what it could offer in terms of speed. During this time, I would continue to use Python as a tool for prototyping. This, it ...
2
votes
2answers
80 views

Django CBVs vs FBVs

For creating a large Django project with many apps, my first initial thought was to used Class Based Views (as the Django tutorials seem to emphasize). However, I noticed that due to a lot of the ...
3
votes
1answer
273 views

Good practice for returns in Python

I was recently working on some prototype code in Python. The code worked great, then I realized that I needed a little more feedback from one of my functions so I changed the return statement from ...
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2answers
114 views

the perils of using eval() for dynamic object creation — is this a valid argument in a consenting-adults culture?

I've read on stackoverflow explicit warnings against using eval() to create objects. The reason that seems to be given is that malicious code could be injected and blindly created objects could ...
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2answers
139 views

Need help understanding a recursion example in Python

Python is my first programming language, and I'm learning it from "How to Think Like a Computer Scientist". In Chapter 5 the author gives the following example on recursion: def factorial(n): if n ...
0
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1answer
80 views

Checking that a function is only run from __main__ in Python

I often end up with code files that can either be imported or run as __main__. It's easy to handle this by checking if __name__ == '__main__'. But sometimes if my main function gets too big I split ...
8
votes
2answers
315 views

Why don't Python and Ruby make a distinction between declaring and assigning a value to variables?

Two of the most popular dynamically typed scripting languages, Python and Ruby, do not make a distinction in syntax between the declaration of a variable and assignation of a value to it. That is in ...
4
votes
2answers
281 views

What are the key differences between Java's and Python's OOP support? [closed]

The only language I've ever used is Java. I like it a lot but decided it's time to learn another language :) . I'm interested in learning Python. It seems like a good choice because it's partly ...
0
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1answer
367 views

Javascript function should call python logic in django web development without additional triiger

I have been trying to solve this problem for sometime now. This is regarding django web development. I have an HTML page which has a Javascript function to upload an image file from the users local ...
3
votes
1answer
75 views

optimize human-readable database with index

i need to store a large amount of data - about 10 million entries of the format unique hash (64 chars), value 1 (5 chars), value 2 (9 chars) i will be reading and deleting (but not updating) this ...
3
votes
2answers
368 views

where exactly should python business logic be placed in django

I have just begun to learn Django/Python/Web Development. This problem has been troubling me for a while now. I am creating an application with multiple templates in Django. I have a views.py which ...
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2answers
228 views

A newbie in python trying to learn [closed]

Am trying to learn how to program before i go to uni and i stumbled upon a question which i have been unable to do. In the function write code to input two integers m and n and calculate and display ...
0
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0answers
26 views

How to deal with multiple output modes of multiple types?

Note: The business domain being a bit complicated to explain, I replaced the names of actual classes by more illustrative examples. I'm writing an application in which the business layer returns a ...
2
votes
2answers
82 views

subclass reference to another subclass

Imagine I have the following code: class A: pass class B(A): pass class C(A): def __init__(self): self.b = B() Is the above code correct in terms of correct inheritance? I ...
0
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0answers
26 views

Defining property and find substitution for copy function of python in cython

I want to cythonize a code in python to speed up the code. In the following you can see my attempt to make my python class understandable for cython: import numpy as np cimport numpy as np ctypedef ...
2
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1answer
90 views

Python API: Extension Module or Pure Module

We have a C++ application, with C++ interfaces changing regularly during development. We also have a C API which is designed to be stable in spite of such changes; the C API is tighly focused on ...
1
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1answer
77 views

Adding new functionality to all of shelve.Shelf's subclasses in Python

In order to avoid the overhead associated with the shelve module's writeback option I'm interested in putting together a shelf class that only accepts hashable values, with hashability being a proxy ...
1
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2answers
165 views

Can a version of Python's shelve module that knows when its entries have been modified be written in any programming language?

shelve is a Python module that makes it easy to persist a Python dictionary to disk (under the right conditions). The documentation for shelve gives this example to demonstrate one of the pitfalls of ...
10
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2answers
218 views

Early attempt to remove Python GIL resulted in bad performance: Why?

This post from Python creator, Guido Van Rossum, mentions an early attempt to remove the GIL from Python: This has been tried before, with disappointing results, which is why I'm reluctant to ...
1
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1answer
89 views

Using class like an object in Python

I am learning from Learn Python the hard way where I have come across a study drill where they want to know that whether a class can be used like an object. As I have experimented: class A(object): ...
0
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1answer
134 views

Measuring performance of a network simulator?

I have written a python program to test a new network routing algorithm, that uses a Content Centric Network Approach for handling requests (CCN), where the CCN router keeps 3 data structures: A ...
0
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0answers
30 views

API providing function to be run in a thread vs. thread that runs this function

I'm writing a Python library which exposes a certain event listener interface. The user can register callbacks to handle different types of events. There is also a function which handles the actual ...
3
votes
2answers
86 views

Object identification in Python

In learning Python, I found that when two "names" (or "variables") are assigned to the same value, both of them point to the same memory address. For example >>> a = 10 >>> b = 10 ...
0
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1answer
2k views

How to avoid Memory Error

I am working with quite large files (pytables) and I am having problems with the Memory Error when I try to load the data for processing. I would like some tips about how to avoid this in my python ...
2
votes
1answer
103 views

Random forest ML algorithm suitable for use on cluster based HPC?

I need help in identifying a better algorithm. I have developed a script using pythons scipy package to analyse a rather large model that I wish to solve. The model contains over 12GB of data ...
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votes
2answers
145 views

Is the tool pywebsocket suited for production? [closed]

Is it a good idea to use pywebsocket in a production environment, since it is so widely used, but their google developer page states "pywebsocket is intended for testing or experimental purposes". ...
2
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0answers
110 views

The inheritance argument of zope.interface (providedby vs isinstance)

What limitations does inheritance of an interface through an abstract base class present that are addressed by zope.interface? In the following talk given in 2010 by Jeff Rush about interfaces, at ...
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votes
2answers
60 views

Minima of a convex list using binary search [closed]

A list is strictly convex if its elements first decrease then increase. How can I write a function in python that accepts a convex list and returns its minima in time complexity O(log(n)), n being the ...
1
vote
2answers
140 views

How would I change the precision of a variable in Python?

I'm working on a 2D-physics engine, and I need a certain variable to be precise only to the hundredths. Are there any methods for basically shaving off all of that unneeded precision? I have tried ...
1
vote
1answer
98 views

Is it possible to have a mutable type that is not garbage collected?

I'm wondering if such a thing can exist. Can there be an object that is mutable but not flagged as garbage collected ( specifically, tp_flags & Py_TPFLAGS_HAVE_GC ) I have a C++ struct-like ...
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votes
1answer
174 views

Is it recommended to use more than one language at a startup? [closed]

I work for a mobile startup where, for historical reasons, our chosen language was C#. I was recently assigned to a small project to build a tool that would be used by us internally. When I explained ...
1
vote
2answers
828 views

Why isn't there a python compiler to native machine code?

As I understand, the cause of the speed difference between compiled languages and python is, that the first compiles code all way to the native machine's code, whereas python compiles to python ...
2
votes
1answer
89 views

Single python file distribution: module or package?

Suppose I have a useful python function or class (or whatever) called useful_thing which exists in a single file. There are essentialy two ways to organize the source tree. The first way uses a single ...
0
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0answers
67 views

Converting large files in python

I have a few files that are ~64GB in size that I think I would like to convert to hdf5 format. I was wondering what the best approach for doing so would be? Reading line-by-line seems to take more ...
1
vote
1answer
246 views

Storing primary keys of objects in Redis and then querying them in Postgres through Django

This is probably my second time posting in programmers. I'm usually on stackoverflow but this question is more fit for the community here. All suggestions, advice and insight on this matter is ...
7
votes
5answers
578 views

Algorithm for flattening overlapping ranges

I am looking for a nice way of flattening (splitting) a list of potentially-overlapping numeric ranges. The problem is very similar to that of this question: Fastest way to split overlapping date ...
8
votes
1answer
412 views

Refactoring a 1500 LOC method that only builds the graphical UI [closed]

I'm currently scratching my head over how to refactor a method that basically only builds the UI. The method is more than 1500 lines of code (LOC) long - and counting. It has grown, there was no plan ...
2
votes
1answer
197 views

Where to implement thread-safety logic for my queue data structure?

I will immediately confess that I do very little multithreading, so questions of style and organization in this domain a little fresh to me. I've written a data structure (in Python, if that matters) ...
0
votes
1answer
101 views

How to write a good mock for testing

I code in Python and I'm starting to use the Mock library. Although I've read through all of the documentation, something that I'm finding hard to understand is 'What makes a good mock'. For ...
0
votes
0answers
63 views

Search substring using suffix array (and LCP)

I'm searching for a best way to improve suffix array run time using LCP. My text (about 2 500 000 chars) seems like: 0ricco0eric0america0polo0.... My thoughs: SA=suffixArray char=firstChar(input) s ...
0
votes
1answer
89 views

“Saving method name in a variable: Python”, How does this code works? [closed]

I am trying to make sense of the following code snipet: factor = misc.kkt_chol2(G, dims, A) .... .... factor(W, P) How the parameter in factor binding with the parameters inside kkt_chol2? Thank ...
0
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1answer
41 views

Python shelve class rename

The main reason I use Shelve is to be able to quickly develop code without worrying about db table structure. Unfortunately changing a class name from, say, 'class1' to 'class2' gives "AttributeError: ...