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Floating point vs integer calculations on modern hardware
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From my experience, there are many, many variables to performance...especially between integer & floating point math. It varies strongly from processor to processor (even within the same family such as x86) because different processors have different "pipeline" lengths. Also, some operations ...
How do I copy an object in Java?
...oes for primitives. For non-primitives, you would just do copy contructor call recursively. e.g. If DummyBean referenced FooBar then FooBar should have contructor FooBar(FooBar another), and dummy should call this.foobar = new FooBar(another.foobar)
– egaga
Feb...
Could not find default endpoint element
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"This error can arise if you are calling the service in a class library and calling the class library from another project."
In this case you will need to include the WS configuration settings into the main projects app.config if its a winapp or web.config i...
How do you test that a Python function throws an exception?
...t ahold of the actual Exception object thrown:
import unittest
def broken_function():
raise Exception('This is broken')
class MyTestCase(unittest.TestCase):
def test(self):
with self.assertRaises(Exception) as context:
broken_function()
self.assertTrue('This i...
Correct way to write line to file?
...ing files opened in text mode (the default); use a single '\n' instead, on all platforms.
Some useful reading:
The with statement
open()
'a' is for append, or use
'w' to write with truncation
os (particularly os.linesep)
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Calling closure assigned to object property directly
...sn't work on a StdClass.
Before PHP7, you'd have to implement the magic __call method to intercept the call and invoke the callback (which is not possible for StdClass of course, because you cannot add the __call method)
class Foo
{
public function __call($method, $args)
{
if(is_...
How do I compare two strings in Perl?
...rldoc perlop for more information.
( I'm simplifying this a little bit as all but cmp return a value that is both an empty string, and a numerically zero value instead of 0, and a value that is both the string '1' and the numeric value 1. These are the same values you will always get from boolean o...
List comprehension vs map
...ing map() over list comprehension or vice versa? Is either of them generally more efficient or considered generally more pythonic than the other?
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How do I concatenate two lists in Python?
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@Daniel it will create a new list with a shallow copy of the items in the first list, followed by a shallow copy of the items in the second list. Use copy.deepcopy to get deep copies of lists.
– Daniel G
Apr 19 '12 at 14:51
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Rails 4 multiple image or file upload using carrierwave
...tiple_image_upload_carrierwave
In gem file
gem 'carrierwave'
bundle install
rails generate uploader Avatar
Create post scaffold
rails generate scaffold post title:string
Create post_attachment scaffold
rails generate scaffold post_attachment post_id:integer avatar:string
rake db:migrate
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