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Ruby.html
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<html>
<head>
<link rel="Stylesheet" type="text/css" href="https://maxcdn.bootstrapcdn.com/bootswatch/3.3.7/cosmo/bootstrap.min.css" />
<title>Ruby</title>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/highlight.js/9.8.0/styles/default.min.css" />
<script src="https://cdnjs.cloudflare.com/ajax/libs/highlight.js/9.8.0/highlight.min.js"></script>
<script>
window.onload = function() {
var allPre, i, j;
allPre = document.getElementsByTagName("pre");
for (i = 0, j = allPre.length; i < j; i++) {
hljs.highlightBlock(allPre[i]);
}
};
</script>
</head>
<body>
<a href="https://github.com/coisnepe/vimwiki_html" class="github-corner" aria-label="View source on Github"><svg width="80" height="80" viewBox="0 0 250 250" style="fill:#151513; color:#fff; position: absolute; top: 0; border: 0; right: 0;" aria-hidden="true"><path d="M0,0 L115,115 L130,115 L142,142 L250,250 L250,0 Z"></path><path d="M128.3,109.0 C113.8,99.7 119.0,89.6 119.0,89.6 C122.0,82.7 120.5,78.6 120.5,78.6 C119.2,72.0 123.4,76.3 123.4,76.3 C127.3,80.9 125.5,87.3 125.5,87.3 C122.9,97.6 130.6,101.9 134.4,103.2" fill="currentColor" style="transform-origin: 130px 106px;" class="octo-arm"></path><path d="M115.0,115.0 C114.9,115.1 118.7,116.5 119.8,115.4 L133.7,101.6 C136.9,99.2 139.9,98.4 142.2,98.6 C133.8,88.0 127.5,74.4 143.8,58.0 C148.5,53.4 154.0,51.2 159.7,51.0 C160.3,49.4 163.2,43.6 171.4,40.1 C171.4,40.1 176.1,42.5 178.8,56.2 C183.1,58.6 187.2,61.8 190.9,65.4 C194.5,69.0 197.7,73.2 200.1,77.6 C213.8,80.2 216.3,84.9 216.3,84.9 C212.7,93.1 206.9,96.0 205.4,96.6 C205.1,102.4 203.0,107.8 198.3,112.5 C181.9,128.9 168.3,122.5 157.7,114.1 C157.9,116.9 156.7,120.9 152.7,124.9 L141.0,136.5 C139.8,137.7 141.6,141.9 141.8,141.8 Z" fill="currentColor" class="octo-body"></path></svg></a>
<a href="index.html">Index</a>
<hr>
<div class="container-fluid">
<div class="row">
<div class="col-md-12">
<div id="Ruby"><h2 id="Ruby">Ruby</h2></div>
<ul>
<li>
<a href="Ruby.html#Array">Array</a>
<li>
<a href="Ruby.html#Enumerator">Enumerator</a>
<li>
<a href="Ruby.html#Hash">Hash</a>
<li>
<a href="Ruby.html#Files&Directories">Files and Directories</a>
<li>
<a href="Ruby.html#csv">csv</a>
<li>
<a href="Ruby.html#Goodies">Goodies</a>
<ul>
<li>
<a href="Ruby.html#Benchmark">Benchmark</a>
</ul>
<li>
<a href="Ruby.html#Random">Random</a>
</ul>
<p>
<br/>
</p>
<div id="Ruby-Core library"><h3 id="Core library">Core library</h3></div>
<div id="Ruby-Core library-Array"><h4 id="Array">Array</h4></div>
<pre class="ruby">
# reject elements. Returns the array without the rejected elements.
["", "1", "2"].reject(&:empty?)
# Select elements. Returns an array.
[10, 2, 1].select { |value| value >= 1 }
# Check elements against a condition. Returns a boolean.
[132, 12, 0.5].any? { |value| value > 1 }
# Select a random element
%w(one two three).sample
# Sort hashes
[{ age: 12, name: "John" }, { age: 21, name: "Betty" }].sort_by { |value_hash| value_hash[:age] }
# Count the number of occurences
%w(one two three one one).count("one") # > 3
# Split in smaller arrays. Returns an enumerator
%w(one two three four five six).each_slice(2)
# > [["one", "two"], ["three", "four"], ["five", "six"]]
# Make an array out of something.
Array.wrap(something)
</pre>
<p>
<br/>
</p>
<div id="Ruby-Core library-Enumerator"><h4 id="Enumerator">Enumerator</h4></div>
<pre class="ruby">
(1..4).each_with_object([]) { |item, ob| ob << item * 10 }
=> [10, 20, 30, 40]
> (1..4).each_with_object({}) { |i, ob| ob[i] = i * 10 }
=> {1=>10, 2=>20, 3=>30, 4=>40}
</pre>
<p>
<br />
</p>
<div id="Ruby-Core library-Hash"><h4 id="Hash">Hash</h4></div>
<p>
Get all keys recursively in a Hash
</p>
<pre class="ruby">
def get_all_keys(ha)
ha.each_with_object([]) do |(key, value), keys|
keys << key
keys.concat(get_all_keys(value)) if value.is_a? Hash
end
end
</pre>
<p>
<br />
</p>
<div id="Ruby-Core library-Files&Directories"><h4 id="Files&Directories">Files&Directories</h4></div>
<p>
Directories
</p>
<pre class="ruby">
Dir.pwd # Current directory
Dir.chdir "take_me_home/directory/" # Change directory
Dir.glob("*") # Array of files' name in pwd
Dir.glob('dir_name/**/*.{avi,m4a}') # Every avi and m4a files, including in sub-directories
Dir["/target_directory/*"] # Array of files' path + name
</pre>
<p>
Files
</p>
<pre class="ruby">
File.basename("my_code.rb")
</pre>
<p>
<br/>
</p>
<div id="Ruby-csv"><h3 id="csv">csv</h3></div>
<p>
Nuclear csv parsing: never see the dreaded <code>invalid byte sequence</code> error ever again
</p>
<pre class="ruby">
csv_file = File.read(file)
.encode("UTF-8", "binary", invalid: :replace, undef: :replace, replace: "")
CSV.parse(csv_file, col_sep: ";", force_quotes: true, encoding: "utf-8")
</pre>
<p>
<br />
</p>
<div id="Ruby-csv-Goodies"><h4 id="Goodies">Goodies</h4></div>
<pre class="ruby">
# Execute unix commands using backticks `. Returns a string
`wc -l line_count.csv`
</pre>
<p>
<br/>
</p>
<div id="Ruby-csv-Goodies-Benchmark"><h5 id="Benchmark">Benchmark</h5></div>
<pre class="ruby">
require "benchmark"
puts Benchmark.measure { "something".capitalize }
iterations = 1_000
Benchmark.bm(iterations) do |bm|
bm.report "message here" do
"something".capitalize
end
bm.report "another convoluted method" do
"something"[0].upcase + "something"[1..-1]
end
end
Benchmark.ips do |x|
x.report("any?") { Actor.any? }
x.report("limit(1)") { Actor.limit(1).count }
x.compare!
end
# Comparison:
# limit(1): 1213.5 i/s
# any?: 597.1 i/s - 2.03x slower
</pre>
<p>
<br />
</p>
<div id="Ruby-csv-Random"><h4 id="Random">Random</h4></div>
<p>
Syntax highlighting of other languages from within ruby code
</p>
<pre class="ruby">
sql_query = <<-SQL
SELECT * FROM users
WHERE is_awesome IS true
SQL
</pre>
<p>
URI Library
</p>
<pre class="ruby">
URI.parse("http://www.github.com")
</pre>
</div>
</div>
</div>
</body>
</html>