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Dynamically select data frame columns using $ and a character value
...e that must first be evaluated in the second argument. You may only pass a string which is never evaluated.
Instead use [ (or [[ if you want to extract only a single column as a vector).
For example,
var <- "mpg"
#Doesn't work
mtcars$var
#These both work, but note that what they return is d...
How to find out element position in slice?
... }
}
return -1
}
And usage:
xs := []int{2, 4, 6, 8}
ys := []string{"C", "B", "K", "A"}
fmt.Println(
SliceIndex(len(xs), func(i int) bool { return xs[i] == 5 }),
SliceIndex(len(xs), func(i int) bool { return xs[i] == 6 }),
SliceIndex(len(ys), func(i int) bool { return ys[i]...
How to get the full url in Express?
...from req.originalUrl (thanks @pgrassant). Note this DOES include the query string. docs here on req.url and req.originalUrl. Depending on what you intend to do with the URL, originalUrl may or may not be the correct value as compared to req.url.
Combine those all together to reconstruct the absolu...
How to prettyprint a JSON file?
...nting this also works without explicit parsing: print json.dumps(your_json_string, indent=4)
– Peterino
Aug 4 '14 at 14:07
11
...
Drag and drop files into WPF
...rmats.FileDrop))
{
// Note that you can have more than one file.
string[] files = (string[])e.Data.GetData(DataFormats.FileDrop);
// Assuming you have one file that you care about, pass it off to whatever
// handling code you have defined.
HandleFileOpen(files[0]);
}
}
Als...
UTF-8, UTF-16, and UTF-32
...ling. The code point is already available right there in your array/vector/string.
– richq
Jan 30 '09 at 17:48
24
...
Copying text to the clipboard using Java
...s for me and is quite simple:
Import these:
import java.awt.datatransfer.StringSelection;
import java.awt.Toolkit;
import java.awt.datatransfer.Clipboard;
And then put this snippet of code wherever you'd like to alter the clipboard:
String myString = "This text will be copied into clipboard";
S...
How to execute a java .class from the command line
...e no valid main method... The signature should be:
public static void main(String[] args);
Hence, in your case the code should look like this:
public class Echo {
public static void main (String[] arg) {
System.out.println(arg[0]);
}
}
Edit: Please note that Oscar is also ri...
Why should a Java class implement comparable?
...
Here is a real life sample. Note that String also implements Comparable.
class Author implements Comparable<Author>{
String firstName;
String lastName;
@Override
public int compareTo(Author other){
// compareTo should return < 0...
How to reference a method in javadoc?
...on, is:
Examples
Method in the same class:
/** See also {@link #myMethod(String)}. */
void foo() { ... }
Method in a different class, either in the same package or imported:
/** See also {@link MyOtherClass#myMethod(String)}. */
void foo() { ... }
Method in a different package and not imported:...