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How do I create an empty array/matrix in NumPy?
...rt numpy
>>> a = numpy.zeros(shape=(5,2))
>>> a
array([[ 0., 0.],
[ 0., 0.],
[ 0., 0.],
[ 0., 0.],
[ 0., 0.]])
>>> a[0] = [1,2]
>>> a[1] = [2,3]
>>> a
array([[ 1., 2.],
[ 2., 3.],
[ 0., 0.],
[ 0., 0.],
[ 0., 0.]])
...
Reduce, fold or scan (Left/Right)?
...first* operator arg `res`
// op: -4 - 4 = -8
// res: Int = -8
xs.foldLeft(0)(minus)
// op: 0 - 1 = -1
// op: -1 - 2 = -3
// op: -3 - 3 = -6
// op: -6 - 4 = -10
// res: Int = -10
xs.scanLeft(0)(minus)
// op: 0 - 1 = -1
// op: -1 - 2 = -3
// op: -3 - 3 = -6
// op: -6 - 4 = -10
// res: List[Int] = Li...
range() for floats
..., this could produce unpredictable results like:
>>> list(frange(0, 100, 0.1))[-1]
99.9999999999986
To get the expected result, you can use one of the other answers in this question, or as @Tadhg mentioned, you can use decimal.Decimal as the jump argument. Make sure to initialize it with...
Truncate number to two decimal places without rounding
...eform.rounded
var with2Decimals = num.toString().match(/^-?\d+(?:\.\d{0,2})?/)[0]
rounded.value = with2Decimals
}
<form onsubmit="return calc(this)">
Original number: <input name="original" type="text" onkeyup="calc(form)" onchange="calc(form)" />
<br />"Rounded" numb...
Fastest way to replace NAs in a large data.table
... a large data.table , with many missing values scattered throughout its ~200k rows and 200 columns. I would like to re code those NA values to zeros as efficiently as possible.
...
How does Dijkstra's Algorithm and A-Star compare?
...
answered Aug 26 '09 at 5:18
leizleiz
3,63622 gold badges2020 silver badges1616 bronze badges
...
Obfuscated C Code Contest 2006. Please explain sykes2.c
...>> ";;;====~$::199"[_*2&8|_/64]/(_&2?1:8)%8&1
: 10);
}
Introducing variables to untangle this mess:
main(int i) {
if(i^448)
main(-~i);
if(--i % 64) {
char a = -~7[__TIME__-i/8%8][">'txiZ^(~z?"-48];
char b = a >> ";;;====~$::199"[i...
What is the significance of initializing direction arrays below with given values when developing ch
... want to add onto its x and its y value to move it to a nearby location, 1,0 is east, -1,0 is west, 0,1 is south, 0,-1 is north and so on.
(Here I have said top left is 0,0 and bottom right is 4,4 and shown what move each index of the arrays will make from the central point, X, at 2,2.)
.....
.536...
Does JavaScript have a method like “range()” to generate a range within the supplied bounds?
...
Numbers
[...Array(5).keys()];
=> [0, 1, 2, 3, 4]
Character iteration
String.fromCharCode(...[...Array('D'.charCodeAt(0) - 'A'.charCodeAt(0) + 1).keys()].map(i => i + 'A'.charCodeAt(0)));
=> "ABCD"
Iteration
for (const x of Array(5).keys()) {
co...
Java synchronized static methods: lock on object or class
... |
edited Nov 1 '16 at 8:02
Ravindra babu
39.4k77 gold badges201201 silver badges180180 bronze badges
a...