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Length of a JavaScript object
...an break enumerations in various libraries. Adding methods to Object is usually safe, though.
Here's an update as of 2016 and widespread deployment of ES5 and beyond. For IE9+ and all other modern ES5+ capable browsers, you can use Object.keys() so the above code just becomes:
var size = Object...
“Large data” work flows using pandas
... one contains different fields, or do they have some records per file with all of the fields in each file?
Do you ever select subsets of rows (records) based on criteria (e.g. select the rows with field A > 5)? and then do something, or do you just select fields A, B, C with all of the records (a...
Multiple returns from a function
...
Technically, you can't return more than one value. However, there are multiple ways to work around that limitation. The way that acts most like returning multiple values, is with the list keyword:
function getXYZ()
{
return arr...
ASP.NET MVC: Is Controller created for every request?
...ther controller.
The short version is that ControllerActivator.Create is called (for every request) to create a Controller (which inits a new Controller either through the DependencyResolver or through the Activator if no Resolver has been set up):
public IController Create(RequestContext requestC...
What does 'super' do in Python?
...
What's the difference?
SomeBaseClass.__init__(self)
means to call SomeBaseClass's __init__. while
super(Child, self).__init__()
means to call a bound __init__ from the parent class that follows Child in the instance's Method Resolution Order (MRO).
If the instance is a subclass of ...
Convert JavaScript string in dot notation into an object reference
...k themselves the question "why am I doing this?"
It is of course generally fine to do this if your use case is small and you will not run into performance issues, AND you won't need to build upon your abstraction to make it more complicated later. In fact, if this will reduce code complexity an...
How to use the PI constant in C++
...
On some (especially older) platforms (see the comments below) you might need to
#define _USE_MATH_DEFINES
and then include the necessary header file:
#include <math.h>
and the value of pi can be accessed via:
M_PI
In my math....
Disable Browser Link - which toolbar
...olbar, but that toolbar doesn't show up in my visual studio. I've enabled all the debug toolbars but still no browser link button.
...
How to atomically delete keys matching a pattern using Redis
...
Starting with redis 2.6.0, you can run lua scripts, which execute atomically. I have never written one, but I think it would look something like this
EVAL "return redis.call('del', unpack(redis.call('keys', ARGV[1])))" 0 prefix:[YOUR_PREFIX e.g delete_me_*]
Warning: As the Redis document sa...
Removing duplicate objects with Underscore for Javascript
...
.uniq/.unique accepts a callback
var list = [{a:1,b:5},{a:1,c:5},{a:2},{a:3},{a:4},{a:3},{a:2}];
var uniqueList = _.uniq(list, function(item, key, a) {
return item.a;
});
// uniqueList = [Object {a=1, b=5}, Object {a=2}, Object {a=3}, Object ...