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Cannot drop database because it is currently in use
...ame'} returns nothing. Yet it till complains. This doesn't seem to actually work.
– Pxtl
Mar 12 at 21:56
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Unable to install gem - Failed to build gem native extension - cannot load such file — mkmf (LoadErr
...
But I have 1.9.3 ruby only.
– Alexandre
Dec 7 '12 at 17:14
5
ruby 1.9.3 is an ...
Convert SQLITE SQL dump file to POSTGRESQL
...h a sequence to that column so that INSERTs with NULL ids will be automatically assigned the next available value. PostgreSQL will also not recognize AUTOINCREMENT commands, so these need to be removed.
You'll also want to check for datetime columns in the SQLite schema and change them to timestamp ...
How to replace a character by a newline in Vim
...s a newline (more precisely, it’s treated as the input CR). Here’s a small, non-interactive example to illustrate this, using the Vim command line feature (in other words, you can copy and paste the following into a terminal to run it). xxd shows a hexdump of the resulting file.
echo bar > te...
Fastest way to duplicate an array in JavaScript - slice vs. 'for' loop
...wer is vastly different. For example cloning an array of listeners before calling each of them. Those arrays are often small, usually 1 element.
– gman
Feb 13 '15 at 2:05
7
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Creating a “logical exclusive or” operator in Java
...new operators in Java.
Edit: Here's an example:
public static void main(String[] args) {
boolean[] all = { false, true };
for (boolean a : all) {
for (boolean b: all) {
boolean c = a ^ b;
System.out.println(a + " ^ " + b + " = " + c);
}
}
}
Ou...
What is the rationale behind having companion objects in Scala?
...xample.
abstract class AnimalCounter
{
var animals = 0
def name: String
def count()
{
animals += 1
println("%d %ss created so far".format(animals, name))
}
}
abstract class Animal
{
def companion: AnimalCounter
companion.count()
}
object Dog extends A...
How do I check if an index exists on a table field in MySQL?
...name, this way you don't need to find out the index name if it is automatically added without name.
– Programista
Apr 9 '14 at 11:05
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Convert one date format into another in PHP
...o be a proper timestamp (seconds since January 1, 1970). You are passing a string, which date() can't recognize.
You can use strtotime() to convert a date string into a timestamp. However, even strtotime() doesn't recognize the y-m-d-h-i-s format.
PHP 5.3 and up
Use DateTime::createFromFormat. It...
data.table vs dplyr: can one do something well the other can't or does poorly?
...j and by together is by design. By keeping related operations together, it allows to easily optimise operations for speed and more importantly memory usage, and also provide some powerful features, all while maintaining the consistency in syntax.
1. Speed
Quite a few benchmarks (though mostly on g...