What does ‘&’ do in a C++ declaration?

The “&” denotes a reference instead of a pointer to an object (In your case a constant reference). The advantage of having a function such as over is that in the former case you are guaranteed that myname is non-null, since C++ does not allow NULL references. Since you are passing by reference, the object …

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What is the difference between {} and [] in python?

columnNames = {} defines an empty dict columnNames = [] defines an empty list These are fundamentally different types. A dict is an associative array, a list is a standard array with integral indices. I recommend you consult your reference material to become more familiar with these two very important Python container types.

How do I break a string in YAML over multiple lines?

Using yaml folded style. The indention in each line will be ignored. A line break will be inserted at the end. http://symfony.com/doc/current/components/yaml/yaml_format.html You can use the “block chomping indicator” to eliminate the trailing line break, as follows: In either case, each line break is replaced by a space. There are other control tools available as …

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How do you comment out code in PowerShell?

In PowerShell V1 there’s only # to make the text after it a comment. In PowerShell V2 <# #> can be used for block comments and more specifically for help comments. For more explanation about .SYNOPSIS and .* see about_Comment_Based_Help. Remark: These function comments are used by the Get-Help CmdLet and can be put before the keyword Function, or inside the {} before or after the code itself.

What’s the meaning of “=>” (an arrow formed from equals & greater than) in JavaScript?

What It Is This is an arrow function. Arrow functions are a short syntax, introduced by ECMAscript 6, that can be used similarly to the way you would use function expressions. In other words, you can often use them in place of expressions like function (foo) {…}. But they have some important differences. For example, they do …

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