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How to rename a single column in a data.frame?
...ewname2"
attempts to set the second column's name. Your object only has one column, so the command throws an error. This should be sufficient:
colnames(trSamp) <- "newname2"
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How To Create a Flexible Plug-In Architecture?
...ot an answer as much as a bunch of potentially useful remarks/examples.
One effective way to make your application extensible is to expose its internals as a scripting language and write all the top level stuff in that language. This makes it quite modifiable and practically future proof (if your...
When is it appropriate to use UDP instead of TCP? [closed]
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This is one of my favorite questions. UDP is so misunderstood.
In situations where you really want to get a simple answer to another server quickly, UDP works best. In general, you want the answer to be in one response packet, and y...
How can I add numbers in a Bash script?
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Yew they are existed but the one variable is double.. is that a problem??
– Nick
Jun 14 '11 at 20:35
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Multidimensional Array [][] vs [,] [duplicate]
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One is an array of arrays, and one is a 2d array. The former can be jagged, the latter is uniform.
That is, a double[][] can validly be:
double[][] x = new double[5][];
x[0] = new double[10];
x[1] = new double[5];
x[2] = ...
Memcached vs. Redis? [closed]
...d at ~225MB. They are similarly efficient in how they store data, but only one is capable of reclaiming it.
Disk I/O dumping: A clear win for redis since it does this by default and has very configurable persistence. Memcached has no mechanisms for dumping to disk without 3rd party tools.
Scaling:...
The relationship could not be changed because one or more of the foreign-key properties is non-nulla
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You should delete old child items thisParent.ChildItems one by one manually. Entity Framework doesn't do that for you. It finally cannot decide what you want to do with the old child items - if you want to throw them away or if you want to keep and assign them to other parent enti...
Is there a Max function in SQL Server that takes two values like Math.Max in .NET?
...al line: "return @value2" to read as: "return isnull(@val2,@val1)" then if one of the values is null the function will return the not null value, otherwise it will work as normal
– kristof
Sep 24 '08 at 10:32
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What are forward declarations in C++?
...unction may live in a different object file the linker is joining with the one that uses add to produce a dll or exe. It's possible that the linker may get the wrong add. Say you wanted to use int add(int a, float b), but accidentally forgot to write it, but the linker found an already existing int ...
Understanding :source option of has_one/has_many through of Rails
Please help me in understanding the :source option of has_one/has_many :through association. The Rails API explanation makes very little sense to me.
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