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data.table vs dplyr: can one do something well the other can't or does poorly?
..., keyby = .(x,y)][DT2][, z := z*mul][]
# dplyr equivalent
DF1 %>% group_by(x, y) %>% summarise(z = sum(z)) %>%
right_join(DF2) %>% mutate(z = z * mul)
2) do it all in one go (using by = .EACHI feature):
DT1[DT2, list(z=sum(z) * mul), by = .EACHI]
What is the advantage?
We do...
Why is the minimalist, example Haskell quicksort not a “true” quicksort?
...x?p=1407357&seqNum=3 -- Andrey Alexandrescu
– The_Ghost
Oct 11 '11 at 17:32
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jQuery: keyPress Backspace won't fire?
...tr('name');
var hiddenID = tempField.substr(tempField.indexOf('_') + 1);
$('#' + hiddenID).val('');
$(this).val('')
return;
} // Allow: tab, escape, and enter
else if (event.keyCode == 9 || event.keyCode == 27 || event.keyCode == 13 ||...
How to deal with persistent storage (e.g. databases) in Docker
...te --name hello
docker run -d -v hello:/container/path/for/volume container_image my_command
This means that the data-only container pattern must be abandoned in favour of the new volumes.
Actually the volume API is only a better way to achieve what was the data-container pattern.
If you create ...
What is the difference between Reader and InputStream?
...s.
Reader reader = new InputStreamReader(inputStream, StandardCharsets.UTF_8);
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git submodule tracking latest
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@DC_ I agree with "this answer" (since I wrote it). The "following a branch" feature is meant to update a submodule to the latest commit of a branch. Once that is done, you will still have to add and commit the new submodule sta...
HTML5 Canvas 100% Width Height of Viewport?
...es the text. You unfortunately have to use JS.
– i336_
May 10 '16 at 1:56
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How can I know when an EditText loses focus?
...
Kotlin way
editText.setOnFocusChangeListener { _, hasFocus ->
if (!hasFocus) { }
}
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How to navigate through textfields (Next / Done Buttons)
...ssumptions can be ignored as well.
Swift 4.0
func textFieldShouldReturn(_ textField: UITextField) -> Bool {
let nextTag = textField.tag + 1
// Try to find next responder
let nextResponder = textField.superview?.viewWithTag(nextTag) as UIResponder!
if nextResponder != nil {
...
How to find all positions of the maximum value in a list?
...t was a little tricky figuring out the proper initialization values for max_val and max_indices which worked for all possible cases, especially if the max happened to be the first value in the list — but I believe it now does.
def maxelements(seq):
''' Return list of position(s) of largest el...