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Pandas every nth row
...umn slice, both based on integer position and following normal python syntax.
df.iloc[::5, :]
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Object comparison in JavaScript [duplicate]
...ursively and access all non-enumerable properties, but this works in Firefox only.
So the best I can do is to guess usage scenarios.
1) Fast and limited.
Works when you have simple JSON-style objects without methods and DOM nodes inside:
JSON.stringify(obj1) === JSON.stringify(obj2)
The OR...
Accessing class variables from a list comprehension in the class definition
...ss scope and list, set or dictionary comprehensions, as well as generator expressions do not mix.
The why; or, the official word on this
In Python 3, list comprehensions were given a proper scope (local namespace) of their own, to prevent their local variables bleeding over into the surrounding sc...
Geometric Mean: is there a built-in?
...ulating geometric mean in R. The verbose mean calculation involving length(x) is necessary for the cases where x contains non-positive values.
gm_mean = function(x, na.rm=TRUE){
exp(sum(log(x[x > 0]), na.rm=na.rm) / length(x))
}
Thanks to @ben-bolker for noting the na.rm pass-through and @Gr...
How can I get the client's IP address in ASP.NET MVC?
...
The simple answer is to use the HttpRequest.UserHostAddress property.
Example: From within a Controller:
using System;
using System.Web.Mvc;
namespace Mvc.Controllers
{
public class HomeController : ClientController
{
public ActionResult Index()
{
string ip ...
What does a lazy val do?
...
The difference between them is, that a val is executed when it is defined whereas a lazy val is executed when it is accessed the first time.
scala> val x = { println("x"); 15 }
x
x: Int = 15
scala> lazy val y = { println("y"); 13 }
y: Int = <lazy>
scala>...
Numpy argsort - what is it doing?
...entation
Returns the indices that would sort an array.
2 is the index of 0.0.
3 is the index of 0.1.
1 is the index of 1.41.
0 is the index of 1.48.
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How does C compute sin() and other math functions?
...2011, this is the code that actually runs when you call sin() on a typical x86-64 Linux system. It is apparently faster than the fsin assembly instruction. Source code: sysdeps/ieee754/dbl-64/s_sin.c, look for __sin (double x).
This code is very complex. No one software algorithm is as fast as poss...
Unicode character for “X” cancel / close?
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It is called 'Heavy Multiplication X' I believe - fileformat.info/info/unicode/char/2716/index.htm
– eipark
Nov 1 '13 at 15:12
8
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Slicing of a NumPy 2d array, or how do I extract an mxm submatrix from an nxn array (n>m)?
I want to slice a NumPy nxn array. I want to extract an arbitrary selection of m rows and columns of that array (i.e. without any pattern in the numbers of rows/columns), making it a new, mxm array. For this example let us say the array is 4x4 and I want to extract a 2x2 array from it.
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