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Should I use a data.frame or a matrix?
When should one use a data.frame , and when is it better to use a matrix ?
6 Answers
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How to securely store access token and secret in Android?
I am going to use oAuth to fetch mails and contacts from google. I don't want to ask the user each time to log in to obtain an access token and secret. From what I understood, I need to store them with my application either in a database or SharedPreferences . But I am a bit worried about security ...
Find the Smallest Integer Not in a List
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If the datastructure can be mutated in place and supports random access then you can do it in O(N) time and O(1) additional space. Just go through the array sequentially and for every index write the value at the index to the index specified by value, recursively placin...
Optimizing away a “while(1);” in C++0x
...oops?, although this is WG14 document the rationale applies to C++ as well and the document refers to both WG14 and WG21:
As N1509 correctly points out, the current draft essentially gives
undefined behavior to infinite loops in 6.8.5p6. A major issue for
doing so is that it allows code to m...
Why does += behave unexpectedly on lists?
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The general answer is that += tries to call the __iadd__ special method, and if that isn't available it tries to use __add__ instead. So the issue is with the difference between these special methods.
The __iadd__ special method is for an in-place addition, that is it mutates the object that it a...
Best way to make Java's modulus behave like it should with negative numbers?
... of the negative values of a, since (a % b) is a negative value between -b and 0, (a % b + b) is necessarily lower than b and positive. The last modulo is there in case a was positive to begin with, since if a is positive (a % b + b) would become larger than b. Therefore, (a % b + b) % b turns it in...
Why should I use Deque over Stack?
...re for my use case. I should be able to push items into the data structure and I only want to retrieve the last item from the Stack. The JavaDoc for Stack says :
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How do you determine the size of a file in C?
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You could probably change the return type to ssize_t and cast the size from an off_t without any trouble. It would seem to make more sense to use a ssize_t :-) (Not to be confused with size_t which is unsigned and cannot be used to indicate error.)
– Ted P...
Does JavaScript guarantee object property order?
... iteration order is a combination of the insertion order for strings keys, and ascending order for number-like keys:
// key order: 1, foo, bar
const obj = { "foo": "foo", "1": "1", "bar": "bar" }
Using an array or a Map object can be a better way to achieve this. Map shares some similarities with O...
How to clear the canvas for redrawing
After experimenting with composite operations and drawing images on the canvas I'm now trying to remove images and compositing. How do I do this?
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