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Different types of thread-safe Sets in Java
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1) The CopyOnWriteArraySet is a quite simple implementation - it basically has a list of elements in an array, and when changing the list, it copies the array. Iterations and other accesses which are running at this time continue with the old ...
How to display length of filtered ng-repeat data
I have a data array which contains many objects (JSON format). The following can be assumed as the contents of this array:
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When to use nil, blank, empty? [duplicate]
...may be used to check on various object types like empty string "" or empty array []
blank? - checks for nil? or empty?.
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Why do I need 'b' to encode a string with Base64?
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Short Answer
You need to push a bytes-like object (bytes, bytearray, etc) to the base64.b64encode() method. Here are two ways:
>>> data = base64.b64encode(b'data to be encoded')
>>> print(data)
b'ZGF0YSB0byBiZSBlbmNvZGVk'
Or with a variable:
>>> string = '...
What's the opposite of chr() in Ruby?
...comment but add the [0]:
'A'.unpack('C')[0]
The unpack call returns an Array containing a single integer, which is not always accepted where an integer is wanted:
$ ruby -e 'printf("0x%02X\n", "A".unpack("C"))'
-e:1:in `printf': can't convert Array into Integer (TypeError)
from -e:1
$ ruby...
Controlling fps with requestAnimationFrame?
...variable in the object each setInterval 'frame'. Keep these objects in an array. Set your interval to your desired fps in ms: ms=(1000/fps). This keeps a steady clock that allows the same fps on any device, regardless of RAF speed. Do not assign the transforms to the elements here!
In a reques...
find vs find_by vs where
...hat you supply. Use where (as described below, which will return an empty array if the attribute is not found) to avoid an exception being thrown.
Other uses of find are usually replaced with things like this:
Model.all
Model.first
find_by is used as a helper when you're searching for informati...
Why are we not to throw these exceptions?
...arly, IndexOutOfRangeExceptions occur when you access an invalid index (on arrays—not lists). You should always make sure that you don’t do that in the first place and check the boundaries of e.g. an array first.
There are a few other exceptions like those two, for example InvalidCastException ...
How to generate a random number between a and b in Ruby?
...ubyinside.com/ruby-1-9-3-introduction-and-changes-5428.html
Converting to array may be too expensive, and it's unnecessary.
(a..b).to_a.sample
Or
[*a..b].sample
Array#sample
Standard in Ruby 1.8.7+.
Note: was named #choice in 1.8.7 and renamed in later versions.
But anyway, generating a...
What are C++ functors and their uses?
...u could pass a MultiplyBy object to an algorithm like std::transform:
int array[5] = {1, 2, 3, 4, 5};
std::transform(array, array + 5, array, MultiplyBy(3));
// Now, array is {3, 6, 9, 12, 15}
Another advantage of a functor over a pointer to a function is that the call can be inlined in more case...