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Using group by on multiple columns
I understand the point of GROUP BY x .
2 Answers
2
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JavaScript listener, “keypress” doesn't detect backspace?
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KeyPress event is invoked only for character (printable) keys, KeyDown event is raised for all including nonprintable such as Control, Shift, Alt, BackSpace, etc.
UPDATE:
The keypress event is fired when a key is pressed down and that key normally produces a character v...
Javascript reduce() on Object
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What you actually want in this case are the Object.values. Here is a concise ES6 implementation with that in mind:
const add = {
a: {value:1},
b: {value:2},
c: {value:3}
}
const total = Object.values(add).reduce((t, {value}) => t + value, 0)
console.log(tota...
How to declare string constants in JavaScript? [duplicate]
I want to declare string constants in JavaScript.
11 Answers
11
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cocktail party algorithm SVD implementation … in one line of code?
In a slide within the introductory lecture on machine learning by Stanford's Andrew Ng at Coursera, he gives the following one line Octave solution to the cocktail party problem given the audio sources are recorded by two spatially separated microphones:
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builder for HashMap
...es (if you need to store nulls take a look at other answers)
produce immutable maps
If we need mutable map (like HashMap) we can use its copy-constructor and let it copy content of map created via Map.of(..)
Map<Integer, String> map = new HashMap<>( Map.of(1,"a", 2,"b", 3,"c") );
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Is well formed without a ?
Is it valid to have <input> without it being in a <form> ?
7 Answers
7
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Ruby on Rails: how to render a string as HTML?
...ning is that, as a security measure, Rails is escaping your string for you because it might have malicious code embedded in it. But if you tell Rails that your string is html_safe, it'll pass it right through.
@str = "<b>Hi</b>".html_safe
<%= @str %>
OR
@str = "<b>Hi</...
Using ls to list directories and their total sizes
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Try something like:
du -sh *
short version of:
du --summarize --human-readable *
Explanation:
du: Disk Usage
-s: Display a summary for each specified file. (Equivalent to -d 0)
-h: "Human-readable" output. Use unit suffixes: B...
How to retry after exception?
I have a loop starting with for i in range(0, 100) . Normally it runs correctly, but sometimes it fails due to network conditions. Currently I have it set so that on failure, it will continue in the except clause (continue on to the next number for i ).
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