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How does one reorder columns in a data frame?
...s keep all the rows, and the 1,2,3,4 refers to the columns.
To change the order as in the above question do df2[,c(1,3,2,4)]
If you want to output this file as a csv, do write.csv(df2, file="somedf.csv")
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How to check identical array in most efficient way? [duplicate]
...t to check if the two arrays are identical
(not content wise, but in exact order).
2 Answers
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Convert integer into byte array (Java)
... look at the ByteBuffer class.
ByteBuffer b = ByteBuffer.allocate(4);
//b.order(ByteOrder.BIG_ENDIAN); // optional, the initial order of a byte buffer is always BIG_ENDIAN.
b.putInt(0xAABBCCDD);
byte[] result = b.array();
Setting the byte order ensures that result[0] == 0xAA, result[1] == 0xBB, ...
C# constructor execution order
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The order is:
Member variables are initialized to default values for all classes in the hierarchy
Then starting with the most derived class:
Variable initializers are executed for the most-derived type
Constructor chaining ...
Efficiency of premature return in a function
...iction or for some other issue where the platform determines the preferred ordering.
– Steve314
Oct 25 '11 at 9:55
6
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Switch statement for greater-than/less-than
...re per case and therefore faster, but still very slow except in Opera. The order of the case statement is important since the engine will test each case in source code order ECMAScript262:5 12.11
switch (true) {
case (val < 1000): /* do something */ break;
case (val < 2000): /* do somethi...
how to read System environment variable in Spring applicationContext
...Denv=QA should solve your problem.
Note also a comment by @yiling:
In order to access system environment variable, that is OS level
variables as amoe commented, we can simply use "systemEnvironment"
instead of "systemProperties" in that EL. Like
#{systemEnvironment['ENV_VARIABLE_NAME']}
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Is there a CSS selector for elements containing certain text?
...s it working just 'cos male is first? Bug waiting to happen if they are re-ordered?
– Michael Durrant
Mar 26 '16 at 22:56
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How to simulate Android killing my process
...tyB onCreate WITHOUT savedInstance
ActivityB onStart
ActivityA onStop (the order is like this, it is stopped after new one is started)
<go settings>
ActivityB onStop
<disable a permission>
//Application is killed, but onDestroy methods are not called.
//Android does not call onDestroy me...
Can I set up HTML/Email Templates with ASP.NET?
...fit of this approach is consistency. For example, you could show a user an order summary and include exactly the same thing in the confirmation email by reusing the same control.
– Mun
Mar 26 '09 at 21:19
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