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What's an elegant way to conditionally add a class to an HTML element in a view?

...lly you should represent success with boolean true or a numeric record ID, and failure with boolean false or nil. This way you can just test your variable: <div class="<%= 'ok' if @success %>"> A second form using the ternary ?: operator is useful if you want to choose between two cl...
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Why Func instead of Predicate?

... While Predicate has been introduced at the same time that List<T> and Array<T>, in .net 2.0, the different Func and Action variants come from .net 3.5. So those Func predicates are used mainly for consistency in the LINQ operators. As of .net 3.5, about using Func<T> and Action...
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How can I use Bash syntax in Makefile targets?

...sed as the shell. So put SHELL := /bin/bash at the top of your makefile, and you should be good to go. BTW: You can also do this for one target, at least for GNU Make. Each target can have its own variable assignments, like this: all: a b a: @echo "a is $$0" b: SHELL:=/bin/bash # HERE: t...
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Why does Unicorn need to be deployed together with Nginx?

I would like to know the difference between Nginx and Unicorn. As far as I understand, Nginx is a web server while Unicorn is a Ruby HTTP server. ...
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What does “default” mean after a class' function declaration?

...e that function automatically. With the introduction of move constructors and move assignment operators, the rules for when automatic versions of constructors, destructors and assignment operators are generated has become quite complex. Using = default and = delete makes things easier as you don't ...
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What's the difference between Sender, From and Return-Path?

What's the difference between an email Sender, From and Return-Path value? 3 Answers 3...
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What does @hide mean in the Android source code?

... Android has two types of APIs that are not accessible via SDK. The first one is located in package com.android.internal. The second API type is a collection of classes and methods that are marked with the @hide Javadoc attr...
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Can I call an overloaded constructor from another constructor of the same class in C#?

...r: yes, using the this keyword. Long answer: yes, using the this keyword, and here's an example. class MyClass { private object someData; public MyClass(object data) { this.someData = data; } public MyClass() : this(new object()) { // Calls the previous constructor ...
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Differences between git remote update and fetch?

...etch Documentation/RelNotes/* | less Then I did a less search for --all, and this is what I found under the release notes for Git version 1.6.6: git fetch learned --all and --multiple options, to run fetch from many repositories, and --prune option to remove remote tracking branches that went ...
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Argparse: Required arguments listed under “optional arguments”?

...sually considered optional. All other parameters are positional parameters and as such required by design (like positional function arguments). It is possible to require optional arguments, but this is a bit against their design. Since they are still part of the non-positional arguments, they will s...