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Which is the fastest algorithm to find prime numbers?
...
Actually I don't think primegen is the fastest, or even the second-fastest; yafu and primesieve are both faster in general, I think, and certainly over 2^32. Both are (modified) sieves of Eratosthenes rather than the Atkin-Berns...
Add new field to every document in a MongoDB collection
...field" : 1, "test" : "a" }
EDIT:
In case you want to add a new_field to all your collection, you have to use empty selector, and set multi flag to true (last param) to update all the documents
db.your_collection.update(
{},
{ $set: {"new_field": 1} },
false,
true
)
EDIT:
In the above ...
Convert SVG to image (JPEG, PNG, etc.) in the browser
...out the need for Canvg, which is a pretty large library because it handles all the SVG parsing that an SVG-supporting browser already provides for free. I'm not sure if this satisfies the original use-case, but if so, then see this resource for details.
– Premasagar
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When to use NSInteger vs. int
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You usually want to use NSInteger when you don't know what kind of processor architecture your code might run on, so you may for some reason want the largest possible integer type, which on 32 bit systems is just an int, while on a ...
How do I list loaded plugins in Vim?
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Not a VIM user myself, so forgive me if this is totally offbase. But according to what I gather from the following VIM Tips site:
" where was an option set
:scriptnames : list all plugins, _vimrcs loaded (super)
:verbose set history? : reveals value of hist...
Bash command to sum a column of numbers [duplicate]
...mn of numbers. I just want a quick one liner that will do something essentially like this:
10 Answers
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Reshaping data.frame from wide to long format
...s melt/cast. Here is a solution with reshape, assuming your data frame is called d:
reshape(d,
direction = "long",
varying = list(names(d)[3:7]),
v.names = "Value",
idvar = c("Code", "Country"),
timevar = "Year",
times = 1950:1954)
...
What are the differences between “=” and “
... The operator <- can be used anywhere,
whereas the operator = is only allowed at the top level (e.g.,
in the complete expression typed at the command prompt) or as one
of the subexpressions in a braced list of expressions.
Let’s not put too fine a point on it: the R documentation is (su...
How to handle WndProc messages in WPF?
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Actually, as far as I understand such a thing is indeed possible in WPF using HwndSource and HwndSourceHook. See this thread on MSDN as an example. (Relevant code included below)
// 'this' is a Window
HwndSource source = HwndSou...
Numpy index slice without losing dimension information
...y an array that might be length 1 at runtime. For that case, there's np.ix_:
some_array[np.ix_(row_index,column_index)]
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