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Simultaneously merge multiple data.frames in a list
I have a list of many data.frames that I want to merge. The issue here is that each data.frame differs in terms of the number of rows and columns, but they all share the key variables (which I've called "var1" and "var2" in the code below). If the data.frames were identical in terms of columns, ...
How to call asynchronous method from synchronous method in C#?
I have a public async void Foo() method that I want to call from synchronous method. So far all I have seen from MSDN documentation is calling async methods via async methods, but my whole program is not built with async methods.
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How to use timeit module
I understand the concept of what timeit does but I am not sure how to implement it in my code.
14 Answers
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Retrieve a Fragment from a ViewPager
I'm using a ViewPager together with a FragmentStatePagerAdapter to host three different fragments:
23 Answers
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Returning from a finally block in Java
I was surprised recently to find that it's possible to have a return statement in a finally block in Java.
6 Answers
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Git ignore file for Xcode projects
...r, but it needs a bit of cleanup, so here it is redone for Xcode 4, with some improvements.
I've researched every file in this list, but several of them do not exist in Apple's official Xcode documentation, so I had to go on Apple mailing lists.
Apple continues to add undocumented files, potential...
Is it good practice to NULL a pointer after deleting it?
...pointer to 0 (which is "null" in standard C++, the NULL define from C is somewhat different) avoids crashes on double deletes.
Consider the following:
Foo* foo = 0; // Sets the pointer to 0 (C++ NULL)
delete foo; // Won't do anything
Whereas:
Foo* foo = new Foo();
delete foo; // Deletes the obj...
Design for Facebook authentication in an iOS app that also accesses a secured web service
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I just dealt with this myself, and here's the part that bit me:
In your step 5... It's possible for a user to register for an account with you entirely separate from their Facebook ID, right? Then some other time they log in with Facebook.... And you just created them a second accoun...
Jackson and generic type reference
I want to use jackson json library for a generic method as follows:
3 Answers
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What's the difference between findAndModify and update in MongoDB?
I'm a little bit confused by the findAndModify method in MongoDB. What's the advantage of it over the update method? For me, it seems that it just returns the item first and then updates it. But why do I need to return the item first? I read the MongoDB: the definitive guide and it says that i...