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Django select only rows with duplicate field values
...values('name')
.annotate(Count('id'))
.order_by()
.filter(id__count__gt=1)
This is as close as you can get with Django. The problem is that this will return a ValuesQuerySet with only name and count. However, you can then use this to construct a regula...
how to bypass Access-Control-Allow-Origin?
...case anyone out there actually needs to bypass this they can use PHP's file_get_contents($remote_url);. There are obviously many ways to do this but this is how I did it.
– Shawn Whinnery
Mar 5 '14 at 23:39
...
How to step through Python code to help debug issues?
...rSummoner, pudb is great for that. Also pydev
– alpha_989
Jun 11 '18 at 19:45
pdb is not a command line tool. To use i...
How do I implement interfaces in python?
...the trick.
from abc import ABCMeta, abstractmethod
class IInterface:
__metaclass__ = ABCMeta
@classmethod
def version(self): return "1.0"
@abstractmethod
def show(self): raise NotImplementedError
class MyServer(IInterface):
def show(self):
print 'Hello, World 2!'
...
Append an object to a list in R in amortized constant time, O(1)?
... 2-element vector named c as is clearly intended!
– j_random_hacker
Dec 5 '11 at 16:45
7
So is th...
Repeat string to certain length
...
def repeat_to_length(string_to_expand, length):
return (string_to_expand * ((length/len(string_to_expand))+1))[:length]
For python3:
def repeat_to_length(string_to_expand, length):
return (string_to_expand * (int(length/len(s...
Ruby: require vs require_relative - best practice to workaround running in both Ruby =1.
... this post.
https://github.com/appoxy/aws/blob/master/lib/awsbase/require_relative.rb
unless Kernel.respond_to?(:require_relative)
module Kernel
def require_relative(path)
require File.join(File.dirname(caller[0]), path.to_str)
end
end
end
This allows you to use require_relati...
Re-raise exception with a different type and message, preserving existing information
...ble to whatever code catches the new exception.
By using this feature, the __cause__ attribute is set. The built-in exception handler also knows how to report the exception's “cause” and “context” along with the traceback.
In Python 2, it appears this use case has no good answer (as describ...
What is the instanceof operator in JavaScript?
...there.
Every object in JavaScript has a prototype, accessible through the __proto__ property. Functions also have a prototype property, which is the initial __proto__ for any objects created by them. When a function is created, it is given a unique object for prototype. The instanceof operator uses...
Extract substring in Bash
Given a filename in the form someletters_12345_moreleters.ext , I want to extract the 5 digits and put them into a variable.
...