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'printf' vs. 'cout' in C++
...e when you print many arguments. If you have to write something like Error 2: File not found., assuming error number, and its description is placeholder, the code would look like this. Both examples work identically (well, sort of, std::endl actually flushes the buffer).
printf("Error %d: %s.\n", i...
How do I get an empty array of any size in python?
...
241
If by "array" you actually mean a Python list, you can use
a = [0] * 10
or
a = [None] * 10...
Determine the number of NA values in a column
...
321
You're over-thinking the problem:
sum(is.na(df$col))
...
How to determine function name from inside a function
...
238
You can use ${FUNCNAME[0]} in bash to get the function name.
...
PHP ORMs: Doctrine vs. Propel
...ria):
<?php
// Propel
$c = new Criteria();
$c->add(ExamplePeer::ID, 20);
$items = ExamplePeer::doSelectJoinFoobar($c);
// Doctrine
$items = Doctrine_Query::create()
->from('Example e')
->leftJoin('e.Foobar')
->where('e.id = ?', 20)
->execute();
?>
...
What is the best practice for “Copy Local” and with project references?
...faultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
<PropertyGroup>
... snip ...
</ItemGroup>
<Import Project="$(MSBuildBinPath)\Microsoft.CSharp.targets" />
<Import Project="[relative path to Common.targets]" />
<!-- To modif...
Rails 3 migrations: Adding reference column?
...
205
If you are using the Rails 4.x you can now generate migrations with references, like this:
ra...
How to convert a negative number to positive?
...
216
>>> n = -42
>>> -n # if you know n is negative
42
>>> abs(n) ...
How to get a Docker container's IP address from the host
...
52 Answers
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What does curly brackets in the `var { … } = …` statements do?
...r with Python, it's similar to this syntax:
>>> a, (b, c) = (1, (2, 3))
>>> a, b, c
(1, 2, 3)
The first code chunk is shorthand for:
var {Hotkey: Hotkey} = require("sdk/hotkeys");
// Or
var Hotkey = require("sdk/hotkeys").Hotkey;
You can rewrite the second code chunk as:
let...