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How to check if an NSDictionary or NSMutableDictionary contains a key?
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And what if the key does exist, but it's corresponding value is nil?
– Fyodor Soikin
May 6 '10 at 21:30
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What is external linkage and internal linkage?
I want to understand the external linkage and internal linkage and their difference.
9 Answers
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Difference between android-support-v7-appcompat and android-support-v4
I wanted to know the difference between android-support-v4.jar
and android-support-v7-appcompat.jar . If I want to add appcompat Action Bar in my application do I need to add both android-support-v7-appcompat.jar and android-support-v4.jar or only android-support-v7-appcompat.jar .
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Why should I prefer to use member initialization lists?
... this case, the constructor for B will call the default constructor for A, and then initialize a.x to 3. A better way would be for B's constructor to directly call A's constructor in the initializer list:
B()
: a(3)
{
}
This would only call A's A(int) constructor and not its default constructo...
How exactly does CMake work?
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The secret is that you don't have to understand what the generated files do.
CMake introduces a lot of complexity into the build system, most of which only pays off if you use it for building complex software projects.
The good news is that CMake does a good job of k...
Invalidating JSON Web Tokens
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I too have been researching this question, and while none of the ideas below are complete solutions, they might help others rule out ideas, or provide further ones.
1) Simply remove the token from the client
Obviously this does nothing for server side security, but it...
How to log something in Rails in an independent log file?
In rails I want to log some information in a different log file and not the standard development.log or production.log. I want to do this logging from a model class.
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How do I check if an object has a specific property in JavaScript?
...king for. If you want to know if an object physically contains a property (and it is not coming from somewhere up on the prototype chain) then object.hasOwnProperty is the way to go. All modern browsers support it. (It was missing in older versions of Safari - 2.0.1 and older - but those versions of...
Extending the User model with custom fields in Django
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The least painful and indeed Django-recommended way of doing this is through a OneToOneField(User) property.
Extending the existing User model
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If you wish to store information related to User, you can use a one-to-one relationship to a mo...
What does ON [PRIMARY] mean?
I'm creating an SQL setup script and I'm using someone else's script as an example. Here's an example of the script:
4 Ans...