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Reshaping data.frame from wide to long format
I have some trouble to convert my data.frame from a wide table to a long table.
At the moment it looks like this:
9 Answe...
How do I use the conditional operator (? :) in Ruby?
...some extra junk after it), but they are not required in the last case as said issue does not arise.
You can use the "long-if" form for readability on multiple lines:
question = if question.size > 20 then
question.slice(0, 20) + "..."
else
question
end
...
Nested attributes unpermitted parameters
...hing like
params.require(:person).permit(:name, :age, pets_attributes: [:id, :name, :category])
Some more details can be found in the Ruby edge API docs and strong_parameters on github or here
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no gravity for scrollview. how to make content inside scrollview as center
I want the content inside the scrollView as center.
7 Answers
7
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How to make a countdown timer in Android?
...
new CountDownTimer(30000, 1000) {
public void onTick(long millisUntilFinished) {
mTextField.setText("seconds remaining: " + millisUntilFinished / 1000);
//here you can have your logic to set text to edittext
}
public void onFinish() {
m...
JPA: How to have one-to-many relation of the same Entity type
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Yes, this is possible. This is a special case of the standard bidirectional @ManyToOne/@OneToMany relationship. It is special because the entity on each end of the relationship is the same. The general case is detailed in Section 2.10.2 of the JPA 2.0 spec.
Here's a worked example. F...
What's the difference between session.Merge and session.SaveOrUpdate?
...n, do nothing
if another object associated with the session has the same identifier,
throw an exception
if the object has no identifier property, save() it
if the object's identifier has the value assigned to a newly
instantiated object, save() it
if the object is versioned (by a <v...
SQL Inner-join with 3 tables?
...owing (I guessed on table fields,etc)
SELECT s.studentname
, s.studentid
, s.studentdesc
, h.hallname
FROM students s
INNER JOIN hallprefs hp
on s.studentid = hp.studentid
INNER JOIN halls h
on hp.hallid = h.hallid
Based on your request for multiple halls you could do it this ...
PHP + MySQL transactions examples
...
The idea I generally use when working with transactions looks like this (semi-pseudo-code):
try {
// First of all, let's begin a transaction
$db->beginTransaction();
// A set of queries; if one fails, an excep...
Android: android.content.res.Resources$NotFoundException: String resource ID #0x5
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I am wondering why Android Studio does not advice you. I had the same problem setting an int value into TextView.setText for error.
– bheatcoker
Apr 22 '16 at 10:08
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