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List distinct values in a vector in R
...els( data$product_code )
If it's not a factor, but it should be, you can convert it to factor first by using the factor() function, e.g.
levels( factor( data$product_code ) )
Another option, as mentioned above, is the unique() function:
unique( data$product_code )
The main difference between...
How can I make the computer beep in C#?
...p().
// Default beep
Console.Beep();
You can also specify the frequency and length of the beep in milliseconds.
// Beep at 5000 Hz for 1 second
Console.Beep(5000, 1000);
For more information refer http://msdn.microsoft.com/en-us/library/8hftfeyw%28v=vs.110%29.aspx
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How to elegantly rename all keys in a hash in Ruby? [duplicate]
... I used this in as_json() call, and although the main attributes keys were converted to string, the options.merge(:methods => [:blah]) then that is a key in the map not a string.
– peterept
Mar 8 '13 at 1:04
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How to center align the cells of a UICollectionView?
I am currently using UICollectionView for the user interface grid, and it works fine. However, I'd like to be enable horizontal scrolling. The grid supports 8 items per page and when the total number of items are, say 4, this is how the items should be arranged with horizontal scroll direction ena...
AngularJS - wait for multiple resource queries to complete
... Your answer is very helpful and I believe it is the most sensible way to convert resources to promises in the current angular. It might be helpful to add that in the documentation of $q, which you linked to, it guarantees that the result array is in the same order as the promise array.
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json.net has key method?
...ing explicit interface implementation, so you can't use them without first converting to IDictionary<string, JToken> though.
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TypeError: 'NoneType' object is not iterable in Python
...'str' and 'NoneType' objects
What's going on here?
Python's interpreter converted your code to pyc bytecode. The Python virtual machine processed the bytecode, it encountered a looping construct which said iterate over a variable containing None. The operation was performed by invoking the __it...
LEN function not including trailing spaces in SQL Server
...st method that gives correct answers that I know of is the following:
LEN(CONVERT(NVARCHAR(MAX), @s) + 'x') - 1
This is faster than the REPLACE technique, and much faster with longer strings. Basically this technique is the LEN(@s + 'x') - 1 technique, but with protection for the edge case where ...
In C#, how to check if a TCP port is available?
...ctionInformation objects, which you can then interrogate about endpoint IP and port.
int port = 456; //<--- This is your value
bool isAvailable = true;
// Evaluate current system tcp connections. This is the same information provided
// by the netstat command line application, just in .Ne...
How to create a temporary directory/folder in Java?
Is there a standard and reliable way of creating a temporary directory inside a Java application? There's an entry in Java's issue database , which has a bit of code in the comments, but I wonder if there is a standard solution to be found in one of the usual libraries (Apache Commons etc.) ?
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