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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8
votes
2answers
343 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
396 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
votes
1answer
896 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
99 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
754 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 ...
0
votes
0answers
28 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
83 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
votes
0answers
44 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
votes
1answer
104 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
vote
1answer
88 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
vote
2answers
280 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 ...
11
votes
2answers
306 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
vote
1answer
108 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
votes
1answer
165 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
votes
0answers
31 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
88 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
votes
1answer
4k 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
134 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 ...
-2
votes
1answer
235 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
votes
0answers
149 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 ...
-1
votes
2answers
76 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
254 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
101 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 ...
-3
votes
1answer
179 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 ...
2
votes
1answer
2k 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 ...
3
votes
1answer
129 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
votes
0answers
71 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
393 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
852 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
422 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
279 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
121 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
1answer
93 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
votes
1answer
48 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: ...
-3
votes
1answer
279 views

Sqlite3 slow on standard queries, is it expected? [closed]

Using Python and sqlite3. This simple print loop takes a few seconds to execute. I don't know much about databases, so I'm guessing I'm not using these queries correctly. Surely sqlite should be ...
4
votes
2answers
185 views

Unit Testing: How much more code? [duplicate]

I'm fairly new to unit testing. In school it's always been, "hey it works, onward!" But I've started to write professionally, and even at work that's been basically the mantra. However, I've started ...
4
votes
2answers
277 views

Should duck typing affect naming conventions?

I'm a C++/C# developer and recently I've started to learn Python. I think I understand the concept of duck typing right now except for one thing. When I'm coding in C++ or C# I sometimes create ...
29
votes
1answer
1k views

How to deal with a misnamed function in production code?

I've recently come across a Python library on GitHub. The library is great, but contains one glaring typo in a function name. Let's call it dummy_fuction() while it should be dummy_function(). This ...
0
votes
1answer
145 views

Is the following example a strategy pattern?

In my problem I had lots of objects with slightly different behaviour, but identical attributes and methodes with identical interfaces. The objects variants were quite big in number, and I didn't want ...
3
votes
0answers
279 views

Why are so many Python files really big (5k+ lines)? [closed]

Is there any specific reason driving Python files to often be so large? Python files may contain several classes within one file, and some files go up over 10k lines in length. This seems to go ...
4
votes
2answers
324 views

Using a closure to avoid code duplication in Python

Sometimes I find myself wanting to run the same code from a few different spots in the same function. Say I have some function func1, and I want to do the same thing from a few different spots in ...
2
votes
0answers
186 views

Gevent - Make blocking calls non-blocking

I have the blocking code shown below. Is calling monkey.patch_all() enough/optimal to make it non-blocking? Does Gevent handle iterations like these? # front page def front_page(): database = ...
-3
votes
1answer
204 views

Is there a purely technical term for 'monkey patching' [closed]

EDIT The original title of the question was Is there a non-derogatory term for 'monkey patching'. As I have learned that the term is actually not derogatory, or is at least not meant to be, I changed ...
1
vote
1answer
95 views

Is it possible to get probabilities from a support vector machine?

From what I understand, SVM's take a discrete number of x and y values from which to learn from, then when given new x values map it to one y value (category). Is it possible to use SVM's or something ...
14
votes
2answers
888 views

Creating nested functions for purely aesthetic reasons?

I've always wondered what other programmers think about the idea of creating pure aesthetic functions. Say I have a function that processes a chunk of data: Function ProcessBigData. Say I need ...
1
vote
2answers
890 views

DDD - Domain Driven Design, which development order should be applied?

1 - Design my entities, ie (in python): class Account: def __init__(name, author): self.name = name self.email = email 2 - Design my repositories: (as interface) class ...
5
votes
2answers
2k views

Why does Python use hash table to implement dict, but not Red-Black Tree? [closed]

Why does Python use hash table to implement dict, but not Red-Black Tree? What is the key? Performance?
3
votes
2answers
587 views

Why do concurrent languages tend to have more complicated syntax?

This is a question that's been on my mind for a while. Recently I've been checking out concurrent languages like Haskell or Go or Erlang. From my point of view, they have huge benefit in performance ...
2
votes
1answer
249 views

Python - Is this a bad strategy pattern?

I've got a Python project wherein a basic object is created and various different attributes are modified/given to it via what I thought was a good example of a strategy pattern. In this silly game ...
1
vote
1answer
120 views

Best way to search through directory structure

I'm working on a python program which organizes a music library. The program will basically help me detect misspelled file or directory names, wrong FLAC tags or unknown/superfluous files. It will ...