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1500 questions
3352
votes
34 answers
"Least Astonishment" and the Mutable Default Argument
Anyone tinkering with Python long enough has been bitten (or torn to pieces) by the following issue:
def foo(a=[]):
a.append(5)
return a
Python novices would expect this function called with no parameter to always return a list with only…
Stefano Borini
- 138,652
- 96
- 297
- 431
3344
votes
12 answers
Improve INSERT-per-second performance of SQLite
Optimizing SQLite is tricky. Bulk-insert performance of a C application can vary from 85 inserts per second to over 96,000 inserts per second!
Background: We are using SQLite as part of a desktop application. We have large amounts of configuration…
Mike Willekes
- 5,960
- 10
- 33
- 33
3343
votes
14 answers
How do I copy a folder from remote to local using scp?
How do I copy a folder from remote to local host using scp?
I use ssh to log in to my server.
Then, I would like to copy the remote folder foo to local /home/user/Desktop.
How do I achieve this?
Slasengger
- 33,707
- 3
- 14
- 10
3339
votes
83 answers
How do I iterate over the words of a string?
How do I iterate over the words of a string composed of words separated by whitespace?
Note that I'm not interested in C string functions or that kind of character manipulation/access. I prefer elegance over efficiency. My current solution:
#include…
Ashwin Nanjappa
- 76,204
- 83
- 211
- 292
3337
votes
31 answers
pretty-print JSON using JavaScript
How can I display JSON in an easy-to-read (for human readers) format? I'm looking primarily for indentation and whitespace, with perhaps even colors / font-styles / etc.
Mark
- 67,098
- 47
- 117
- 162
3326
votes
42 answers
Why is "using namespace std;" considered bad practice?
I have heard using namespace std; is bad practice, and that I should use std::cout and std::cin directly instead.
Why is this? Does it risk declaring variables that share the same name as something in the std namespace?
akbiggs
- 34,001
- 6
- 25
- 36
3315
votes
27 answers
What does ** (double star/asterisk) and * (star/asterisk) do for parameters?
What do *args and **kwargs mean in these function definitions?
def foo(x, y, *args):
pass
def bar(x, y, **kwargs):
pass
See What do ** (double star/asterisk) and * (star/asterisk) mean in a function call? for the complementary question…
Todd
- 34,500
- 4
- 23
- 13
3310
votes
51 answers
How can I check if an object is an array?
I'm trying to write a function that either accepts a list of strings, or a single string. If it's a string, then I want to convert it to an array with just the one item so I can loop over it without fear of an error.
So how do I check if the…
mpen
- 272,448
- 266
- 850
- 1,236
3294
votes
13 answers
How do you push a tag to a remote repository using Git?
I added a tag to the master branch on my machine:
git tag mytag master
How do I push this to the remote repository? Running git push gives the message:
Everything up-to-date
However, the remote repository does not contain my tag.
Jonas
- 121,568
- 97
- 310
- 388
3292
votes
34 answers
Initialization of an ArrayList in one line
I wanted to create a list of options for testing purposes. At first, I did this:
ArrayList places = new ArrayList();
places.add("Buenos Aires");
places.add("Córdoba");
places.add("La Plata");
Then, I refactored the code as…
Macarse
- 91,829
- 44
- 175
- 230
3284
votes
17 answers
How can I delete a file or folder in Python?
How can I delete a file or folder in Python?
Zygimantas
- 33,165
- 6
- 21
- 23
3259
votes
40 answers
How do I pass a variable by reference?
I wrote this class for testing:
class PassByReference:
def __init__(self):
self.variable = 'Original'
self.change(self.variable)
print(self.variable)
def change(self, var):
var = 'Changed'
When I tried…
David Sykes
- 48,469
- 17
- 71
- 80
3259
votes
34 answers
How do I make git use the editor of my choice for editing commit messages?
How do I globally configure git to use a particular editor (e.g. vim) for commit messages?
brasskazoo
- 76,030
- 23
- 64
- 76
3256
votes
15 answers
Why does my JavaScript code receive a "No 'Access-Control-Allow-Origin' header is present on the requested resource" error, while Postman does not?
Mod note: This question is about why XMLHttpRequest/fetch/etc. on the browser are subject to the Same Access Policy restrictions (you get errors mentioning CORB or CORS) while Postman is not. This question is not about how to fix a "No…
Mr Jedi
- 33,658
- 8
- 30
- 40
3252
votes
20 answers
How to iterate over a dictionary?
I've seen a few different ways to iterate over a dictionary in C#. Is there a standard way?
Jake Stewart
- 32,729
- 3
- 20
- 17