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How to delete a row by reference in data.table?
...y reference yet.
data.table can add and delete columns by reference since it over-allocates the vector of column pointers, as you know. The plan is to do something similar for rows and allow fast insert and delete. A row delete would use memmove in C to budge up the items (in each and every column)...
In Rails - is there a rails method to convert newlines to ?
...mat which does exactly what you are looking for, and slightly better since it also adds paragraph tags. See
http://api.rubyonrails.org/classes/ActionView/Helpers/TextHelper.html#method-i-simple_format
Example:
simple_format(mystring)
Note that simple_format allows basic HTML tags, but also pa...
How to run multiple shells on Emacs
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C-u M-x shell will do it.
It will prompt for a name for the new shell, just hit return for the default (which will be something like *shell*<2>.
Also works with eshell.
Another trick, if you use eshell: just as M-x eshell takes you back t...
C#: Printing all properties of an object [duplicate]
Is there a method built in to .NET that can write all the properties and such of an object to the console? Could make one using reflection of course, but I'm curious to if this already exists... especially since you can do it in Visual Studio in the Immediate Window. There you can an object name (wh...
Is floating point math broken?
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Binary floating point math is like this. In most programming languages, it is based on the IEEE 754 standard. The crux of the problem is that numbers are represented in this format as a whole number times a power of two; rational numbers (such as 0.1, which is 1/10) whose denominator is not a pow...
What is the effect of extern “C” in C++?
...le that contains just the declaration of your function. Your function definition is contained in a binary format (that was compiled by your C++ compiler) that the client C linker will then link to using the C name.
Since C++ has overloading of function names and C does not, the C++ compiler cannot j...
SharedPreferences.onSharedPreferenceChangeListener not being called consistently
... preference change listener like this (in the onCreate() of my main activity):
8 Answers
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How to get the body's content of an iframe in Javascript?
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The exact question is how to do it with pure JavaScript not with jQuery.
But I always use the solution that can be found in jQuery's source code.
It's just one line of native JavaScript.
For me it's the best, easy readable and even afaik the shortest way ...
Most efficient way to check for DBNull and then assign to a variable?
...follow
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edited Jan 24 '18 at 10:50
community wiki
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What's the best way to communicate between view controllers?
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These are good questions, and its great to see that you're doing this research and seem concerned with learning how to "do it right" instead of just hacking it together.
First, I agree with the previous answers which focus on the importance of putting da...