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Understanding FFT output
... imaginative part of a complex number (that what's your real and imaginary array is). Instead you want to look for the magnitude of the frequency which is defined as sqrt (real * real + imag * imag). This number will always be positive. Now all you have to search is for the maximum value (ignore the...
getting the last item in a javascript object
...na and so on. If you need to rely on ordering, your best bet is to go with arrays. The power of key-value data structures lies in accessing values by their keys, not in being able to get the nth item of the object.
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Remove an item from array using UnderscoreJS
...sing plain JavaScript, this has been answered already: remove objects from array by object property.
Using underscore.js, you could combine .findWhere with .without:
var arr = [{
id: 1,
name: 'a'
}, {
id: 2,
name: 'b'
}, {
id: 3,
name: 'c'
}];
//substract third
arr = _...
Watch multiple $scope attributes
...oup(['foo', 'bar'], function(newValues, oldValues, scope) {
// newValues array contains the current values of the watch expressions
// with the indexes matching those of the watchExpression array
// i.e.
// newValues[0] -> $scope.foo
// and
// newValues[1] -> $scope.bar
});
...
How to retrieve the first word of the output of a command in bash?
...
I think one efficient way is the use of bash arrays:
array=( $string ) # do not use quotes in order to allow word expansion
echo ${array[0]} # You can retrieve any word. Index runs from 0 to length-1
Also, you can directly read arrays in a pipe-line:
echo "word1 w...
In-place type conversion of a NumPy array
Given a NumPy array of int32 , how do I convert it to float32 in place ? So basically, I would like to do
6 Answers
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How can I reverse a NSArray in Objective-C?
I need to reverse my NSArray .
18 Answers
18
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What is the memory consumption of an object in Java?
... space. (Should I use a 32- or a 64-bit JVM?, 2012, JDK 1.7)
Boxed types, arrays, and strings
Boxed wrappers have overhead compared to primitive types (from JavaWorld):
Integer: The 16-byte result is a little worse than I expected because an int value can fit into just 4 extra bytes. Using ...
Create numpy matrix filled with NaNs
...need loops for vector operations in numpy.
You can create an uninitialized array and assign to all entries at once:
>>> a = numpy.empty((3,3,))
>>> a[:] = numpy.nan
>>> a
array([[ NaN, NaN, NaN],
[ NaN, NaN, NaN],
[ NaN, NaN, NaN]])
I have timed th...
Null coalescing in powershell
...nditional member access for members: ?.
Null-conditional member access for arrays et al: ?[]
These have a few caveats:
Since these are experimental, they're subject to change. They may no longer be considered experimental by the time you read this, and the list of caveats may have changed.
Vari...