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What happens when a duplicate key is put into a HashMap?
...me as well! I did have to add a "remove" method to it to perform the same functionality as a normal Map but worked great!
– JGlass
Oct 16 '18 at 17:20
1
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Standardize data columns in R
... a dataframe and all the columns are numeric you can simply call the scale function on the data to do what you want.
dat <- data.frame(x = rnorm(10, 30, .2), y = runif(10, 3, 5))
scaled.dat <- scale(dat)
# check that we get mean of 0 and sd of 1
colMeans(scaled.dat) # faster version of appl...
Why does Boolean.ToString output “True” and not “true”
...Microsoft can really answer that question. However, I'd like to offer some fun facts about it ;)
First, this is what it says in MSDN about the Boolean.ToString() method:
Return Value
Type: System.String
TrueString if the value of this
instance is true, or FalseString if
the value ...
Can you supply arguments to the map(&:method) syntax in Ruby?
...
I like this solution, but I think you can have even more fun with it. Instead of defining a with method, define call. Then you can do things like a.map(&:+.(2)) since object.() uses the #call method. And while you're at it, you can write fun things like :+.(2).(3) #=> 5 -...
Does Java read integers in little endian or big endian?
...mats that use some form of Huffman encoding (i.e. all of them). For extra fun, JPEG is "bitwise big-endian" (i.e. the most significant bit is the "first" bit) and LZ is "bitwise little-endian". I once worked on a proprietary compression format that used both formats under the hood. Oh, that was f...
Is there a way to get a collection of all the Models in your Rails app?
...ase. Don't know how you can list all the classes though...
EDIT: Just for fun, I found a way to list all classes
Module.constants.select { |c| (eval c).is_a? Class }
EDIT: Finally succeeded in listing all models without looking at directories
Module.constants.select do |constant_name|
constan...
How to detect when an Android app goes to the background and come back to the foreground
...to a Google I/O talk:
class YourApplication : Application() {
override fun onCreate() {
super.onCreate()
registerActivityLifecycleCallbacks(AppLifecycleTracker())
}
}
class AppLifecycleTracker : Application.ActivityLifecycleCallbacks {
private var numStarted = 0
override fun ...
How can I parse a local JSON file from assets folder into a ListView?
...using below code.
and then you can simply read this string return by this function as
public String loadJSONFromAsset() {
String json = null;
try {
InputStream is = getActivity().getAssets().open("yourfilename.json");
int size = is.available();
byte[] buffer = new b...
How to search through all Git and Mercurial commits in the repository for a certain string?
...ways to do that. See "hg help revsets", esp the desc(), user(), and file() functions. There are also hg log switches for most of this behavior. In my experience, though -k/keyword() is usually the most helpful way to search for things.
– Kevin Horn
Dec 17 '12...
How can I make a horizontal ListView in Android? [duplicate]
...) There is no recycling of views. Maybe it would be possible to tack this functionality onto the scroll view, but it seems to me that it would mess with the scrolling behavior, and it would be nearly as much work as simply extending AdapterView.
– Neil Traft
O...