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Why are quaternions used for rotations?
I'm a physicist, and have been learning some programming, and have come across a lot of people using quaternions for rotations instead of writing things in matrix/vector form.
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AJAX POST and Plus Sign ( + ) — How to Encode?
I'm POSTing the contents of a form field via AJAX to a PHP script and using JavaScript to escape(field_contents) . The problem is that any plus signs are being stripped out and replaced by spaces. How can I safely 'encode' the plus sign and then appropriately 'decode' it on the PHP side?
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Question mark and colon in JavaScript
...rm of: condition ? value-if-true : value-if-false
Think of the ? as "then" and : as "else".
Your code is equivalent to
if (max != 0)
hsb.s = 255 * delta / max;
else
hsb.s = 0;
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How to test if list element exists?
...es(foo) # TRUE
"b" %in% names(foo) # TRUE
"c" %in% names(foo) # FALSE
...and foo[["a"]] is safer than foo$a, since the latter uses partial matching and thus might also match a longer name:
x <- list(abc=4)
x$a # 4, since it partially matches abc
x[["a"]] # NULL, no match
[UPDATE] So, back t...
Split list into multiple lists with fixed number of elements
...rate question. Scala has a mysterious gnome that chooses a data structure, and it chose a Stream for you. If you want a List, you should request a List, but you can also just trust the gnome's judgment.
– Ion Freeman
Jun 21 '17 at 21:09
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Using R to download zipped data file, extract, and import data
... of online csvs are zipped. Is there a way to download, unzip the archive, and load the data to a data.frame using R? #Rstats"
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Dispelling the UIImage imageNamed: FUD
...Feb 2014: Note that this question dates from iOS 2.0! Image requirements and handling have moved on a lot since then. Retina makes images bigger and loading them slightly more complex. With the built in support for iPad and retina images, you should certainly use ImageNamed in your code .
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In Python, how does one catch warnings as if they were exceptions?
... warnings. I want to be able to use the try except syntax to properly handle these warnings. Is there a way to do this?
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String.IsNullOrWhiteSpace in LINQ Expression
...NOT (([t0].[Diameter] IS NULL) OR (LTRIM(RTRIM([t0].[Diameter])) = @p0))
and for Linq to SQL almost but not quite the same
DECLARE @p0 NVarChar(1000) = ''
...
WHERE NOT (LTRIM(RTRIM([t0].[TypeName])) = @p0)
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How to determine equality for two JavaScript objects?
...ortant to determine whether any two instances of MyClass are equal, only a and b are important. In some cases c might vary between instances and yet not be significant during comparison.
Note this issue applies when members may themselves also be instances of a type and these each would all be req...