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SQL set values of one column equal to values of another column in the same table
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Sounds like you're working in just one table so something like this:
update your_table
set B = A
where B is null
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Plot two graphs in same plot in R
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lines() or points() will add to the existing graph, but will not create a new window. So you'd need to do
plot(x,y1,type="l",col="red")
lines(x,y2,col="green")
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Behaviour of increment and decrement operators in Python
I notice that a pre-increment/decrement operator can be applied on a variable (like ++count ). It compiles, but it does not actually change the value of the variable!
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When does Java's Thread.sleep throw InterruptedException?
...hen does Java's Thread.sleep throw InterruptedException? Is it safe to ignore it? I am not doing any multithreading. I just want to wait for a few seconds before retrying some operation.
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Find out whether Chrome console is open
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requestAnimationFrame (Late 2019)
Leaving these previous answers here for historical context. Currently Muhammad Umer's approach works on Chrome 78, with the added advantage of detecting both close and open events.
function toString (2019)
Credit to Overcl9ck's comment on this answer. Replacing ...
#pragma once vs include guards? [duplicate]
I'm working on a codebase that is known to only run on windows and be compiled under Visual Studio (it integrates tightly with excel so it's not going anywhere). I'm wondering if I should go with the traditional include guards or use #pragma once for our code. I would think letting the compiler de...
how to get the host url using javascript from the current page
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var host = window.location.hostname;
or possibly
var host = "http://"+window.location.hostname;
or if you like concatenation
var protocol = location.protocol;
var slashes = protocol.concat("//");
var host = slashes.concat(window.location.hostname);
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How do I obtain crash-data from my Android application?
...h data (stack traces at least) from my Android application? At least when working on my own device being retrieved by cable, but ideally from any instance of my application running on the wild so that I can improve it and make it more solid.
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Unique constraint that allows empty values in MySQL
I have a field that stores product codes. The codes are unique, but some products simply doesn't have a code. I can't invent codes because those are providers codes.
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jQuery: serialize() form and other parameters
Is it possible to send form elements (serialized with .serialize() method) and other parameters with a single AJAX request?
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