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Pandas every nth row
...simpler solution to the accepted answer that involves directly invoking df.__getitem__.
df = pd.DataFrame('x', index=range(5), columns=list('abc'))
df
a b c
0 x x x
1 x x x
2 x x x
3 x x x
4 x x x
For example, to get every 2 rows, you can do
df[::2]
a b c
0 x x x
...
What does numpy.random.seed(0) do?
...
If you set the np.random.seed(a_fixed_number) every time you call the numpy's other random function, the result will be the same:
>>> import numpy as np
>>> np.random.seed(0)
>>> perm = np.random.permutation(10)
>>> p...
What is mattr_accessor in a Rails module?
... couldn't really find this in Rails documentation but it seems like 'mattr_accessor' is the Module corollary for 'attr_accessor' (getter & setter) in a normal Ruby class .
...
How to use dashes in HTML-5 data-* attributes in ASP.NET MVC
...an underscore.
For example:
@Html.TextBoxFor(vm => vm.City, new { data_bind = "foo" })
will render this in MVC 3:
<input data-bind="foo" id="City" name="City" type="text" value="" />
If you're still using an older version of MVC, you can mimic what MVC 3 is doing by creating this sta...
What are rvalues, lvalues, xvalues, glvalues, and prvalues?
... three: lvalue, xvalue, prvalue. A Venn diagram would look like this:
______ ______
/ X \
/ / \ \
| l | x | pr |
\ \ / /
\______X______/
gl r
Examples with functions:
int prvalue();
int& lvalue();
int&& xvalue();
But al...
Force browser to clear cache
... changes, one way is to to "cache busting" is by appending something like "_versionNo" to the file name for each release. For example:
script_1.0.css // This is the URL for release 1.0
script_1.1.css // This is the URL for release 1.1
script_1.2.css // etc.
Or alternatively do it after the fil...
Is there a short contains function for lists?
..., you may also be interested to know that what in does is to call the list.__contains__ method, that you can define on any class you write and can get extremely handy to use python at his full extent.
A dumb use may be:
>>> class ContainsEverything:
def __init__(self):
retu...
What breaking changes are introduced in C++11?
...bc"
const char *s = u8"def"; // Previously "abcdef", now "def"
#define _x "there"
"hello"_x // now a user-defined-string-literal. Previously, expanded _x .
New keywords: alignas, alignof, char16_t, char32_t, constexpr, decltype, noexcept, nullptr, static_assert, and thread_local
Ce...
Custom thread pool in Java 8 parallel stream
...gt;
// Parallel task here, for example
IntStream.range(1, 1_000_000).parallel()
.filter(PrimesPrint::isPrime)
.boxed().collect(Collectors.toList())
).get();
System.out.println(primes);
} catch (InterruptedException | ExecutionException e) {
...
Trusting all certificates with okHttp
...Factory, trustAllCerts[0] as X509TrustManager)
.hostnameVerifier { _, _ -> true }.build()
}
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