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What is the Ruby (spaceship) operator?
...ther language that supports it. Basically instead of returning 1 (true) or 0 (false) depending on whether the arguments are equal or unequal, the spaceship operator will return 1, 0, or −1 depending on the value of the left argument relative to the right argument.
a <=> b :=
if a < b t...
Creating a CSS3 box-shadow on all sides but one
...paddings) and add shadow
#content {
font-size: 1.8em;
box-shadow: 0 0 8px 2px #888; /* line shadow */
}
add shadows to tabs:
#nav li a {
margin-left: 20px;
padding: .7em .5em .5em .5em;
font-size: 1.3em;
color: #FFF;
display: inline-block;
text-transform: uppercas...
Best way of returning a random boolean value
...alse].sample is faster than rand(2) == 1. When I performed each operation 10 million times the rand method was 2.179s. The sample method was 1.645s.
– Mirror318
Jun 27 '16 at 4:47
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Is SQL or even TSQL Turing Complete?
...
Qantas 94 Heavy
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answered Sep 28 '11 at 7:59
Jan de VosJan de Vos
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ValueError: math domain error
... |
edited Sep 3 '17 at 20:49
answered Apr 8 '13 at 23:06
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Pandas dataframe get first row of each group
...column:
>>> df.groupby('id').first().reset_index()
id value
0 1 first
1 2 first
2 3 first
3 4 second
4 5 first
5 6 first
6 7 fourth
To get n first records, you can use head():
>>> df.groupby('id').head(2).reset_index(drop=True)
id value
0 ...
What does the constant 0.0039215689 represent?
...
0.0039215689 is approximately equal to 1/255.
Seeing that this is OpenGL, performance is probably important. So it's probably safe to guess that this was done for performance reasons.
Multiplying by the reciprocal is faster...
C# 5 async CTP: why is internal “state” set to 0 in generated code before EndAwait call?
...t. Many thanks to him - and please visit his blog, which rocks.
The value 0 here is only special because it's not a valid state which you might be in just before the await in a normal case. In particular, it's not a state which the state machine may end up testing for elsewhere. I believe that usin...
Insert a row to pandas dataframe
...df.sort_index() # sorting by index
And you get, as desired:
A B C
0 2 3 4
1 5 6 7
2 7 8 9
See in Pandas documentation Indexing: Setting with enlargement.
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Javascript seconds to minutes and seconds
...
To get the number of full minutes, divide the number of total seconds by 60 (60 seconds/minute):
var minutes = Math.floor(time / 60);
And to get the remaining seconds, multiply the full minutes with 60 and subtract from the total seconds:
var seconds = time - minutes * 60;
Now if you also wan...