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How to get indices of a sorted array in Python
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11 Answers
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How to swap keys and values in a hash
...was inverted (in essence, by letting you access keys through values):
{a: 1, b: 2, c: 3}.key(1)
=> :a
If you want to keep the inverted hash, then Hash#invert should work for most situations:
{a: 1, b: 2, c: 3}.invert
=> {1=>:a, 2=>:b, 3=>:c}
BUT...
If you have duplicate values,...
How to know if two arrays have the same values
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function arraysEqual(_arr1, _arr2) {
if (!Array.isArray(_arr1) || ! Array.isArray(_arr2) || _arr1.length !== _arr2.length)
return false;
var arr1 = _arr1.concat().sort();
var arr2 = _arr2.concat().sort();
for (var i = 0; i &l...
How can I add a help method to a shell script?
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177
here's an example for bash:
usage="$(basename "$0") [-h] [-s n] -- program to calculate the an...
Why does Eclipse complain about @Override on interface methods?
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How to find the JVM version from a program?
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10 Answers
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What is the difference between return and return()?
I tested the above code in Chrome's console, and both returned 1 .
9 Answers
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quick random row selection in Postgres
...ith OFFSET, as in
SELECT myid FROM mytable OFFSET floor(random()*N) LIMIT 1;
The N is the number of rows in mytable. You may need to first do a SELECT COUNT(*) to figure out the value of N.
Update (by Antony Hatchkins)
You must use floor here:
SELECT myid FROM mytable OFFSET floor(random()*N) L...
CPU Privilege Rings: Why rings 1 and 2 aren't used?
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114
As a hobbyist operating system writer, I found that because paging (a major part of the modern...