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How to check if an element is in an array
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Swift 2, 3, 4, 5:
let elements = [1, 2, 3, 4, 5]
if elements.contains(5) {
print("yes")
}
contains() is a protocol extension method of SequenceType (for sequences of Equatable elements) and not a global method as in
earlier rel...
What does @hide mean in the Android source code?
For the Activity source code , line 3898 (close to the bottom):
3 Answers
3
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Why should I prefer single 'await Task.WhenAll' over multiple awaits?
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edited Jun 25 '19 at 16:31
answered Aug 19 '13 at 10:02
u...
Jackson: how to prevent field serialization
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edited May 13 '18 at 10:32
narendra-choudhary
3,57433 gold badges2727 silver badges4646 bronze badges
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std::vector versus std::array in C++
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326
std::vector is a template class that encapsulate a dynamic array1, stored in the heap, that gr...
How do I explicitly specify a Model's table-name mapping in Rails?
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437
Rails >= 3.2 (including Rails 4+ and 5+):
class Countries < ActiveRecord::Base
self.ta...
How to determine if an NSDate is today?
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310
In macOS 10.9+ & iOS 8+, there's a method on NSCalendar/Calendar that does exactly this!
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What is the difference between NaN and None?
...= pd.Series([1, None], dtype=object)
s_good = pd.Series([1, np.nan])
In [13]: s_bad.dtype
Out[13]: dtype('O')
In [14]: s_good.dtype
Out[14]: dtype('float64')
Jeff comments (below) on this:
np.nan allows for vectorized operations; its a float value, while None, by definition, forces object ty...
Can anyone explain python's relative imports?
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3 Answers
3
Active
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how to permit an array with strong parameters
I have a functioning Rails 3 app that uses has_many :through associations which is not, as I remake it as a Rails 4 app, letting me save ids from the associated model in the Rails 4 version.
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