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Best way to represent a fraction in Java?
...arable<BigFraction>
{
private static final long serialVersionUID = 1L; //because Number is Serializable
private final BigInteger numerator;
private final BigInteger denominator;
public final static BigFraction ZERO = new BigFraction(BigInteger.ZERO, BigInteger.ONE, true);
public fin...
dplyr summarise: Equivalent of “.drop=FALSE” to keep groups with zero length in output
...e .drop argument that does just what you asked for:
df = data.frame(a=rep(1:3,4), b=rep(1:2,6))
df$b = factor(df$b, levels=1:3)
df %>%
group_by(b, .drop=FALSE) %>%
summarise(count_a=length(a))
#> # A tibble: 3 x 2
#> b count_a
#> <fct> <int>
#> 1 1 ...
How can I create a correlation matrix in R?
...
104
An example,
d &lt- data.frame(x1=rnorm(10),
x2=rnorm(10),
...
Is it possible to specify your own distance function using scikit-learn K-Means Clustering?
...l
from scipy.sparse import issparse # $scipy/sparse/csr.py
__date__ = "2011-11-17 Nov denis"
# X sparse, any cdist metric: real app ?
# centres get dense rapidly, metrics in high dim hit distance whiteout
# vs unsupervised / semi-supervised svm
#..........................................
What's the best practice to round a float to 2 decimals? [duplicate]
...
160
I was working with statistics in Java 2 years ago and I still got the codes of a function that...
How can I redirect the output of the “time” command?
...
104
you can redirect the time output using,
(time ls) &> file
Because you need to take (...
Intersection of two lists in Bash
...
291
comm -12 <(ls 1) <(ls 2)
...
Scala list concatenation, ::: vs ++
...
Legacy. List was originally defined to be functional-languages-looking:
1 :: 2 :: Nil // a list
list1 ::: list2 // concatenation of two lists
list match {
case head :: tail => "non-empty"
case Nil => "empty"
}
Of course, Scala evolved other collections, in an ad-hoc manner....
How to reshape data from long to wide format
...
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Difference between signed / unsigned char [duplicate]
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134
There's no dedicated "character type" in C language. char is an integer type, same (in that re...