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Postgresql aggregate array
...
Use array_agg: http://www.sqlfiddle.com/#!1/5099e/1
SELECT s.name, array_agg(g.Mark) as marks
FROM student s
LEFT JOIN Grade g ON g.Student_id = s.Id
GROUP BY s.Id
By the way, if you are using Postgres 9.1, you don't ...
What is the proper way to re-throw an exception in C#? [duplicate]
...ementation details.
Or you could do your own checking:
public CopyTo(T[] array, int arrayIndex)
{
if(array == null)
throw new ArgumentNullException("array");
if(arrayIndex < 0)
throw new ArgumentOutOfRangeException("arrayIndex", "Array Index must be zero or greater.");
if(Count &g...
sort object properties and JSON.stringify
My application has a large array of objects, which I stringify and save them to the disk. Unfortunately, when the objects in the array are manipulated, and sometimes replaced, the properties on the objects are listed in different orders (their creation order?). When I do JSON.stringify() on the arr...
Permutations in JavaScript?
...
If you notice, the code actually splits the chars into an array prior to do any permutation, so you simply remove the join and split operation
var permArr = [],
usedChars = [];
function permute(input) {
var i, ch;
for (i = 0; i < input.length; i++) {
ch = in...
How to join int[] to a character separated string in .NET?
I have an array of integers:
11 Answers
11
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How do I filter an array with AngularJS and use a property of the filtered object as the ng-model at
If I have an array of objects, and I want to bind the Angular model to a property of one of the elements based on a filter, how do I do that? I can explain better with a concrete example:
...
Does JavaScript have a built in stringbuilder class?
...de for Internet Explorer make sure you chose an implementation, which uses array joins. Concatenating strings with the + or += operator are extremely slow on IE. This is especially true for IE6. On modern browsers += is usually just as fast as array joins.
When I have to do lots of string concaten...
SortedList, SortedDictionary and Dictionary
...like SortedDictionary, however, items in a SortedList are stored as sorted array of items. This means that insertions and deletions are linear - O(n) - because deleting or adding an item may involve shifting all items up or down in the list. Lookup time, however is O(log n) because the SortedList ca...
JSON encode MySQL results
...
$sth = mysqli_query($conn, "SELECT ...");
$rows = array();
while($r = mysqli_fetch_assoc($sth)) {
$rows[] = $r;
}
print json_encode($rows);
The function json_encode needs PHP >= 5.2 and the php-json package - as mentioned here
NOTE: mysql is deprecated as of PHP 5.5....
How can I do an asc and desc sort using underscore.js?
...[1, 2, 3]
But you can use the .reverse method to get it descending:
var array = _.sortBy([2, 3, 1], function(num) {
return num;
});
console.log(array); // [1, 2, 3]
console.log(array.reverse()); // [3, 2, 1]
Or when dealing with numbers add a negative sign to the return to descend the list...