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Reference - What does this error mean in PHP?
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Notice: Undefined Index
Happens when you try to access an array by a key that does not exist in the array.
A typical example of an Undefined Index notice would be (demo)
$data = array('foo' => '42', 'bar');
echo $data['spinach'];
echo $data[1];
Both spinach and 1 do not exis...
How can I explode and trim whitespace?
For example, I would like to create an array from the elements in this string:
11 Answers
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What is the difference between .map, .every, and .forEach?
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The difference is in the return values.
.map() returns a new Array of objects created by taking some action on the original item.
.every() returns a boolean - true if every element in this array satisfies the provided testing function. An important difference with .every() is that ...
How to count the number of true elements in a NumPy bool array
I have a NumPy array 'boolarr' of boolean type. I want to count the number of elements whose values are True . Is there a NumPy or Python routine dedicated for this task? Or, do I need to iterate over the elements in my script?
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Correct way to find max in an Array in Swift
...function (here, it's anonymous) to the accumulator and each element of the array successively, and stores the new value in the accumulator. The last accumulator value is then returned.
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How can I reverse a list in Python?
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You can make use of the reversed function for this as:
>>> array=[0,10,20,40]
>>> for i in reversed(array):
... print(i)
Note that reversed(...) does not return a list. You can get a reversed list using list(reversed(array)).
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What is the equivalent of MATLAB's repmat in NumPy
... dimensions and gives a similar result to matlab. (Numpy gives a 3d output array as you would expect - matlab for some reason gives 2d output - but the content is the same).
Matlab:
>> repmat([1;1],[1,1,1])
ans =
1
1
Python:
In [46]: a = np.array([[1],[1]])
In [47]: np.tile(a, ...
How to get the index of a maximum element in a numpy array along one axis
I have a 2 dimensional NumPy array. I know how to get the maximum values over axes:
4 Answers
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How to extract numbers from a string and get an array of ints?
...ecified number of numbers) and I'd like to extract all the numbers into an array of integers. I was wondering whether there was a quick solution with regular expressions?
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How to convert int[] to Integer[] in Java?
...ed to Integer[] easily:
int[] data = {1,2,3,4,5,6,7,8,9,10};
// To boxed array
Integer[] what = Arrays.stream( data ).boxed().toArray( Integer[]::new );
Integer[] ever = IntStream.of( data ).boxed().toArray( Integer[]::new );
// To boxed list
List<Integer> you = Arrays.stream( data ).boxed...