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How can I check if a key exists in a dictionary? [duplicate]
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if key in array:
# do something
Associative arrays are called dictionaries in Python and you can learn more about them in the stdtypes documentation.
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Are Swift variables atomic?
... you, i.e.:
class Car {
static let sharedCar: Car = Car() // will be called inside of dispatch_once
}
private let sharedCar: Car2 = Car2() // same here
class Car2 {
}
Update 05/25/16: Keep an eye out for swift evolution proposal https://github.com/apple/swift-evolution/blob/master/proposals...
How to iterate over rows in a DataFrame in Pandas
... From the documentation: "Iterating through pandas objects is generally slow. In many cases, iterating manually over the rows is not needed[...]". Your answer is correct (in the context of the question) but does not mention this anywhere, so it isn't a very good one.
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Check if an element is present in an array [duplicate]
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ECMAScript 2016 incorporates an includes() method for arrays that specifically solves the problem, and so is now the preferred method.
[1, 2, 3].includes(2); // true
[1, 2, 3].includes(4); // false
[1, 2, 3].includes(1, 2); // false (second parameter is the index position in this array at...
jquery data selector
...an see the available operators in the code below. Amongst them is ~= which allows regex testing:
$('a:data(category~=^mus..$,artist.name~=^M.+a$)');
I've tested it with a few variations and it seems to work quite well. I'll probably add this as a Github repo soon (with a full test suite), so keep...
Can you use @Autowired with static fields?
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In short, no. You cannot autowire or manually wire static fields in Spring. You'll have to write your own logic to do this.
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The mysql extension is deprecated and will be removed in the future: use mysqli or PDO instead [dupl
...hy is this happening?
The entire ext/mysql PHP extension, which provides all functions named with the prefix mysql_, was officially deprecated in PHP v5.5.0 and removed in PHP v7.
It was originally introduced in PHP v2.0 (November 1997) for MySQL v3.20, and no new features have been added since 2...
How to change the timeout on a .NET WebClient object
...>
Public Class WebClient
Inherits System.Net.WebClient
Private _TimeoutMS As Integer = 0
Public Sub New()
MyBase.New()
End Sub
Public Sub New(ByVal TimeoutMS As Integer)
MyBase.New()
_TimeoutMS = TimeoutMS
End Sub
''' <summary>
''' S...
Django gives Bad Request (400) when DEBUG = False
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The ALLOWED_HOSTS list should contain fully qualified host names, not urls. Leave out the port and the protocol. If you are using 127.0.0.1, I would add localhost to the list too:
ALLOWED_HOSTS = ['127.0.0.1', 'localhost']
You...
How to exit if a command failed?
...on-zero).
Using ( ) makes the command inside them run in a sub-shell and calling a exit from there causes you to exit the sub-shell and not your original shell, hence execution continues in your original shell.
To overcome this use { }
The last two changes are required by bash.
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