Questions tagged [python]

Python is a dynamically typed, high-level interpreted programming 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 and exceptions, and has an extensive standard module library. Python is general-purpose and thus used widely, from the web to embedded systems.

86
votes
9answers
22k views

Check First vs Exception Handling?

I'm working through the book "Head First Python" (it's my language to learn this year) and I got to a section where they argue about two code techniques: Checking First vs Exception handling. Here is ...
43
votes
7answers
10k views

Are small amounts of functional programming understandable by non-FP people? [closed]

Case: I'm working at a company, writing an application in Python that is handling a lot of data in arrays. I'm the only developer of this program at the moment, but it will probably be used/modified/...
78
votes
8answers
103k views

Why use try … finally without a catch clause?

The classical way to program is with try ... catch. When is it appropriate to use try without catch? In Python the following appears legal and can make sense: try: #do work finally: #do ...
21
votes
4answers
8k views

Are there any negative side effects of splitting up large modules? [closed]

I was browsing a github project and found this module which has more than 10 thousand lines. Is it a common practice to have that much code in a single module? It seems to me that this should be ...
147
votes
24answers
196k views

What are the drawbacks of Python? [closed]

Python seems all the rage these days, and not undeservingly - for it is truly a language with which one almost enjoys being given a new problem to solve. But, as a wise man once said (calling him a ...
97
votes
8answers
17k views

Are there any design patterns that are unnecessary in dynamic languages like Python?

I've started reading the design pattern book by the GoF. Some patterns seem very similar with only minor conceptual differences. Do you think out of the many patterns some are unnecessary in a ...
43
votes
4answers
6k views

Python Forgiveness vs. Permission and Duck Typing

In Python, I often hear that it is better to "beg forgiveness" (exception catching) instead of "ask permission" (type/condition checking). In regards to enforcing duck typing in Python, is this try: ...
12
votes
6answers
2k views

As a beginning programmer, should I favor building my own libraries over using 3rd-party libraries?

As a beginning Python programmer, is it a good idea to build and understand my own libraries before jumping to advanced 3rd-party libraries that contains the functionality I need? Some projects (e.g. ...
10
votes
6answers
10k views

How does rapid prototyping fit into an agile methodology?

I work for a large company, which dictates the use of agile processes. For example, for our projects, we use cloud-based services that are specifically targeted at managing agile development. The ...
18
votes
1answer
867 views

What are the problems python 3 new features solve? [closed]

Python 3 new features say: we’re mostly fixing well-known annoyances and warts, and removing a lot of old cruft It mentions what is different (the fix) but not why (the problems). I have have ...
1
vote
1answer
950 views

Unevenly distributed random number generation [duplicate]

Let's say I have to generate random number from 1 to 100, however, the probability of each number is not 1/100, but a predefined probability. How to generate that number? I use Ruby/Python.
0
votes
1answer
1k views

How do I create every permutation [closed]

I have a list of letters, this is just an example list: ['a','b','c','d','e'] How do I compute every combination of the list? The letters cannot repeat, for example. a,b,c,d,e a,c,b,d,e a,c,d,b,e a,...
48
votes
6answers
128k views

How do I learn Python from zero to web development? [closed]

I am looking into learning Python for web development. Assuming I already have some basic web development experience with Java (JSP/Servlets), I'm already familiar with web design (HTML, CSS, JS), ...
139
votes
1answer
93k views

Module vs. Package?

Whenever I do from 'x' import 'y' I was wondering which one is considered the 'module' and which is the 'package', and why it isn't the other way around?
75
votes
5answers
136k views

Is Python Interpreted or Compiled?

This is just a wondering I had while reading about interpreted and compiled languages. Ruby is no doubt an interpreted language since the source code is processed by an interpreter at the point of ...
131
votes
15answers
27k views

Is it always a best practice to write a function for anything that needs to repeat twice?

Myself, I can't wait to write a function when I need to do something more than twice. But when it comes to things that only appear twice, it's a bit more tricky. For code that needs more than two ...
22
votes
7answers
13k views

Learning to program in C (coming from Python) [closed]

If this is the wrong place to ask this question, please let me know. I'm a Python programmer by occupation. I would love to learn C. Indeed, I have tried many times, but I always get discouraged. In ...
71
votes
7answers
18k views

How bad of an idea is it to use Python files as configuration files?

I've always used JSON files for configuration of my applications. I started using them from when I coded a lot of Java, and now I'm working mainly on server-side and data science Python development ...
20
votes
6answers
7k views

Best practices in comment writing and documentation

Commenting nowadays is easier than ever. In Java, there are some nice techniques for linking comments to classes, and Java IDEs are good at making comment shells for you. Languages like Clojure even ...
46
votes
5answers
34k views

Why doesn't Python allow multi-line lambdas?

Can someone explain the concrete reasons why BDFL choose to make Python lambdas single line? This is good: lambda x: x**x This results in an error: lambda x: x**x I understand that making ...
22
votes
2answers
10k views

SQLite with two python processes accessing it: one reading, one writing

I'm developing a small system with two components: one polls data from an internet resource and translates it into sql data to persist it locally; the second one reads that sql data from the local ...
18
votes
8answers
5k views

What are good unit tests to cover the use case of rolling a die?

I'm trying to get to grips with unit testing. Say we have a die which can has a default number of sides equal to 6 (but can be 4, 5 sided etc.): import random class Die(): def __init__(self, ...
13
votes
5answers
13k views

When should use of database be preferred over parsing data from a text file?

I was making a Python program to measure the growth of codereview.SE. My approach was to get the "Site stats" shown on the front page and store them on my hard drive. I plan to do this once every day. ...
16
votes
5answers
8k 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 ...
15
votes
4answers
4k views

Why do some programmers categorize C, Python, C++ differently? - regarding level

I am taking an introductory course on python and the instructor says that python is a high level language and C and C++ are low level languages. It's just confusing. I thought that C, C++, Python, ...
12
votes
2answers
5k views

Are exceptions for flow control best practice in Python?

I'm reading "Learning Python" and have come across the following: User-defined exceptions can also signal nonerror conditions. For instance, a search routine can be coded to raise an exception ...
9
votes
3answers
1k views

What are the challenges related to typing in writing a compiler for a dynamically typed language?

In this talk, Guido van Rossum is talking (27:30) about attempts to write a compiler for Python code, commenting on it saying: turns out it's not so easy to write a compiler that maintains all the ...
7
votes
6answers
13k views

Why should we use low level languages if a high level one like python can do almost everything? [closed]

I know python is not suitable for things like microcontrolers, make drivers etc, but besides that, you can do everything using python, companys get stuck with speed optimizations for real hard time ...
6
votes
3answers
12k views

How to use multiple programming languages together in the same program? [closed]

Such a simple question, but I have not found a reasonable answer to this. I currently program in Python, an interpreted language. I always hear of people using multiple languages in the same program? ...
21
votes
9answers
14k views

Is it essential to learn algorithms to be a real programmer? [closed]

I'm a PHP programmer, and until now I have not needed to learn algorithms... Now I'm start learning Python (a real programming language), because I need to use matplotlib. Does it make sense to start ...
13
votes
2answers
2k views

Object oriented vs vector based programming

I am torn between object oriented and vector based design. I love the abilities, structure and safety that objects give to the whole architecture. But at the same time, speed is very important to me, ...
3
votes
3answers
1k views

How do I test my code in Python other than by doing it by hand?

I am used to user testing in Java, and I also manually test each section of code I write, but now, I want to automate it. There is no GUI for this project, so user testing is not required and I can ...
3
votes
2answers
1k views

Why do ruby and python seem to have more community contribution than PHP? [closed]

In a recent blog post by Roy Osherove, it is pointed out that his switch from primarily .Net development to ruby development has seen a huge difference in community involvement and really enjoys it. ...
2
votes
4answers
1k views

Multiple attribution in Python, JS, …?

I accidentally discovered this a=b=c=d=e=f=2 in python(2.7)(and JavaScript a few minutes later) interpreter . Is this a feature or just the way the interpreter works, if is a feature how it is ...
1
vote
1answer
2k views

Is circular Dependency Injection a good practice?

I'm trying the Dependency Injection pattern in some new classes, more specifically in a Transaction System and stumbled into a dilemma. I have a Person class with a create_new_transaction method, and ...
1
vote
3answers
1k 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 ...
8
votes
2answers
849 views

Should I prefer Python generators to lists?

Python iterators can be very memory efficient. Should I always prefer to use generators instead of just lists? In what situations should I prefer a plain array? For example instead of this: emails = ...
8
votes
3answers
1k views

Microservices and shared libraries

We are designing a system based on independent microservices (connected via a RabbitMq bus). The code will (for the first components at least) be written in python (both python2 and python3). We have ...
6
votes
2answers
1k views

Why does the word “Pythonic” exist? [closed]

Honestly, I hate the word "Pythonic" -- it's used as a simple synonym of "good" in many circles, and I think that's pretentious. Those who use it are silently saying that good code cannot be written ...
5
votes
2answers
3k views

Every function is a closure?

Wikipedia says, that closure - is a function, which has an access to variables, declared outside of the function. There is even an example: function startAt(x) function incrementBy(y) ...
7
votes
2answers
320 views

Version control for code that contains student exercises

I have a fairly substantial Python project that I have developed as an educational endeavor. The version of the code that shall be given to students has exercises throughout, in the form of code that ...
6
votes
2answers
690 views

Writing functional tests for a legacy project

I am trying to add a couple of tests to a legacy C project. The project basically consists of a command line tool that prints something to stdout every time an event happens. Now, since writing unit ...
5
votes
8answers
14k views

Should I store x,y coordinates as an array, a class object, or two variables?

I have a MyObject which has an x and y coordinate. as far as I can see, I can store it in three ways: class MyObject: def __init__(self, x, y): self.x = x self.y = y class ...
5
votes
3answers
737 views

How to avoid large function arity / exposure of underlying implementation

Currently reading Clean Code, and the authors seem to imply that any function with an arity greater than 3 should be avoided at all costs. I am unfortunately running into an issue where I am faced ...
220
votes
9answers
70k views

Why do people hesitate to use Python 3?

Python 3 was released in December 2008. A lot of time has passed since then but still today many developers hesitate to use Python 3. Even popular frameworks like Django are not compatible with Python ...
168
votes
23answers
23k views

Programming cleanly when writing scientific code

I don't really write large projects. I'm not maintaining a huge database or dealing with millions of lines of code. My code is primarily "scripting" type stuff - things to test mathematical ...
138
votes
8answers
183k views

'import module' vs. 'from module import function'

I have always been using this method: from sys import argv and use argv with just argv. But there is a convention of using this: import sys and using the argv by sys.argv The second method makes ...
106
votes
10answers
77k views

Why is Python used for high-performance/scientific computing (but Ruby isn't)?

There's a quote from a PyCon 2011 talk that goes: At least in our shop (Argonne National Laboratory) we have three accepted languages for scientific computing. In this order they are C/C++, ...
29
votes
5answers
102k views

Why doesn't Python need a compiler?

Just wondering (now that I've started with C++ which needs a compiler) why Python doesn't need a compiler? I just enter the code, save it as an exec, and run it. In C++ I have to make builds and all ...
36
votes
3answers
68k views

What are “class methods” and “instance methods”, in Python?

There has been a discussion in chat relating to a question (the question itself being irrelevant to this one), that has revealed I may not know Python whatsoever. In my mind, although terminology ...