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LISTAGG in Oracle to return distinct values
...c and later:
select listagg(distinct the_column, ',') within group (order by the_column)
from the_table
18c and earlier:
select listagg(the_column, ',') within group (order by the_column)
from (
select distinct the_column
from the_table
) t
If you need more columns, something like this ...
How to find the kth smallest element in the union of two sorted arrays?
...
You've got it, just keep going! And be careful with the indexes...
To simplify a bit I'll assume that N and M are > k, so the complexity here is O(log k), which is O(log N + log M).
Pseudo-code:
i = k/2
j = k - i
step = k/4
while step > 0
if a[i-1]...
Multiple left-hand assignment with JavaScript
...
function good() {
var var1 = 1, var2 = 1, var3 = 1;
}
function bad() {
var var1 = var2 = var3 = 1;
}
good();
console.log(window.var2); // undefined
bad();
console.log(window.var2); // 1. Aggh!
Actually this shows that assignment are right associative. The bad example i...
Convert a Python list with strings all to lowercase or uppercase
I have a python list variable that contains strings. Is there a python function that can convert all the strings in one pass to lowercase and vice versa, uppercase?
...
Convert nullable bool? to bool
How do you convert a nullable bool? to bool in C#?
11 Answers
11
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When are you supposed to use escape instead of encodeURI / encodeURIComponent?
When encoding a query string to be sent to a web server - when do you use escape() and when do you use encodeURI() or encodeURIComponent() :
...
Intersection and union of ArrayLists in Java
Are there any methods to do so? I was looking but couldn't find any.
23 Answers
23
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How do you cast a List of supertypes to a List of subtypes?
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Simply casting to List<TestB> almost works; but it doesn't work because you can't cast a generic type of one parameter to another. However, you can cast through an intermediate wildcard type and it will be allowed (since you can cast to and from wil...
Unicode equivalents for \w and \b in Java regular expressions?
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Source code
The source code for the rewriting functions I discuss below is available here.
Update in Java 7
Sun’s updated Pattern class for JDK7 has a marvelous new flag, UNICODE_CHARACTER_CLASS, which makes everything work right again. It’s available as an embeddable (?U) for inside ...
Javascript reduce on array of objects
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After the first iteration your're returning a number and then trying to get property x of it to add to the next object which is undefined and maths involving undefined results in NaN.
try returning an object contain an x property with the sum of the x properties of the pa...