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Why are quaternions used for rotations?
... because they can do more than rotations. But in the case of rotations the extra components are determined in terms of the others.
– JMP
Jan 18 '12 at 23:45
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Plot two graphs in same plot in R
...es(y=y2), colour="green") # second layer
Here + operator is used to add extra layers to basic object.
With ggplot you have access to graphical object on every stage of plotting. Say, usual step-by-step setup can look like this:
g <- ggplot(df, aes(x))
g <- g + geom_line(aes(y=y1), colour=...
Reference — What does this symbol mean in PHP?
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@AcidShout $a - $b works for numbers, but not strings, objects, or arrays.
– mcrumley
Sep 25 '15 at 18:29
49
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How do I trim leading/trailing whitespace in a standard way?
...ferably standard method of trimming leading and trailing whitespace from a string in C? I'd roll my own, but I would think this is a common problem with an equally common solution.
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How to make an AJAX call without jQuery?
...be more convenient than a 'simple' callback? Is this convenience worth the extra effort to transpile it for old browser support?
– lennyklb
Apr 24 '17 at 12:13
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powershell - extract file name and extension
... extension and there may be more dots in the name, so I need to search the string from the right and when I find first dot (or last from the left), extract the part on the right side and the part on the left side from that dot.
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c#: getter/setter
...at it meant. I know they are getters and setters, but want to know why the string Type is defined like this. Thanks for helping me.
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Where can I learn how to write C code to speed up slow R functions? [closed]
...rikes me is that you find R somewhat tedious (data manipulation, graphics, string manipulatio, etc ...). Well get prepared for many more surprises with the internal C API of R. This is very tedious.
From time to time, I read the R-exts or R-ints manuals. This helps. But most of the time, when I re...
Difference between clustered and nonclustered index [duplicate]
... every row in your table. This can be anything, really - an INT, a GUID, a string - pick what makes most sense for your scenario.
2) the clustering key (the column or columns that define the "clustered index" on the table) - this is a physical storage-related thing, and here, a small, stable, ever-...
How can I get the concatenation of two lists in Python without modifying either one? [duplicate]
...>> sum([True, True, False], False)
2
With the notable exception of strings:
>>> sum(['123', '345', '567'], '')
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: sum() can't sum strings [use ''.join(seq) instead]
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