Update ruby notes, small update to docker run note

Author: Yutsuten

notes/language/ruby/array.md

@@ -6,26 +6,35 @@ ref: https://docs.ruby-lang.org/en/3.4/Array.html
 ## Basic
 
 ```ruby
+my_array = Array.new
 my_array = [1, 2, 3]
 my_array = (1..10).to_a
 
 my_array[1]
 my_array.push(40)
 my_array << 40  # Same as push
-
 ```
 
 ## Methods
 
 | Method     | Description                                                       |
 | ---------- | ----------------------------------------------------------------- |
 | `push`     | Appends each argument to the array.                               |
+| `max`      | Returns the biggest element in the array.                         |
+| `min`      | Returns the smallest element in the array                         |
+| `include?` | Returns `true` if the array includes the specified element.       |
 | `sort`     | Returns a new array sorted.                                       |
 | `sort_by!` | Sort in place by using the given block.                           |
 | `reverse`  | Returns a new array in inverse order.                             |
 | `map`      | Returns a new array with each element updated by the given block. |
 | `collect`  | Same as `map`.                                                    |
 
+Check if array includes an element:
+
+```ruby
+my_array.include? 'critical'
+```
+
 Update elements order:
 
 ```ruby

notes/language/ruby/builtin.md

@@ -12,12 +12,22 @@ irb
 
 ## Functions
 
+Simple printing:
+
 ```ruby
-print "Hello"  # Prints something and do NOT put a new line
-puts "Hello"   # Prints something and puts a new line at the end
+print 'Hello'  # Prints something and do NOT put a new line
+puts 'Hello'   # Prints something and puts a new line at the end
+```
 
-puts "My name is #{name}!"
+[String formatting](https://docs.ruby-lang.org/en/3.4/format_specifications_rdoc.html):
 
+```ruby
+sprintf('%.1f', 8.199)
+```
+
+Getting user input:
+
+```ruby
 my_name = gets  # Gets the input from the user
 my_name = gets.chomp  # Same as gets but removes the new line
 ```

notes/language/ruby/control_flow.md

@@ -1,5 +1,6 @@
 ---
 title: Control flow
+ref: https://docs.ruby-lang.org/en/3.4/syntax/control_expressions_rdoc.html
 ---
 
 ## Condition
@@ -25,6 +26,64 @@ do_something unless cond
 cond ? was_true : was_false
 ```
 
+## Loop
+
+```ruby
+loop do
+  next if cond  # Same as continue, skip this iteration
+  do_something
+  break if cond
+end
+```
+
+## For loop
+
+```ruby
+## Include last number
+for num in 1..10
+  puts num
+end
+
+## Exclude last number
+for num in 1...10
+  puts num
+end
+```
+
+## While loop
+
+```ruby
+while cond
+  do_something
+end
+
+until cond
+  do_something
+end
+```
+
+## Do while loop
+
+`do` + `end` is the same as `{` + `}`.
+
+```ruby
+95.upto(100) do |num|
+  puts num
+end
+
+95.downto(90) do |num|
+  puts num
+end
+
+my_array.each do |item|
+  do_something
+end
+
+10.times do
+  do_something
+end
+```
+
 ## Switch
 
 ```ruby

notes/language/ruby/basic_types.md notes/language/ruby/data_types.md

@@ -1,32 +1,36 @@
 ---
-title: Basic types
+title: Data types
 ---
 
 ## Types
 
 ```ruby
-my_name = "Taro"    # String
+my_name = 'Taro'    # String
 my_int = 10         # Integer
 my_float = 3.14
 my_bool = true
 my_nil = nil
 my_symbol = :hello  # Symbol
 ```
 
+Check the type of a variable:
+
+```ruby
+my_var.class
+```
+
+## Type conversion
+
 To convert between types:
 
 ```ruby
 my_name.to_sym  # to symbol
 my_name.intern  # to symbol
 my_symbol.to_s  # to string
+my_str.to_f     # to float
 ```
 
-Number operations:
-
-```ruby
-my_int.next     # Add 1 to an integer
-my_float.floor  # Round down
-```
+## Common methods
 
 Check if an object can receive a method:
 
@@ -43,5 +47,5 @@ my_name.capitalize!
 Methods that return boolean use `?`:
 
 ```ruby
-string_to_check.include? "substring"
+string_to_check.include? 'substring'
 ```

notes/language/ruby/hash.md

@@ -5,25 +5,41 @@ ref: https://docs.ruby-lang.org/en/3.4/Hash.html
 
 ## Basic
 
+Create empty hash:
+
 ```ruby
 my_hash = Hash.new
-my_hash = Hash.new("default value")
-my_hash["id"] = 1
-my_hash.delete(key)
+my_hash = {}
+```
+
+Create filled hash:
 
+```ruby
 my_hash = {
-  "name" => "Taro",
-  "age" => 24
+  'name' => 'Taro',
+  'age' => 24,
 }
 my_hash = {
-  :name => "Taro",
-  :age => 24
+  :name => 'Taro',
+  :age => 24,
 }
 my_hash = {
-  name: "Taro",
-  age: 24
+  name: 'Taro',  # Becomes symbol
+  age: 24,       # Becomes symbol
 }
+```
+
+Access values of a hash:
 
+```ruby
+my_hash['id'] = 1
+my_hash[:id] = 1
+my_hash.delete(key)
+```
+
+## Methods
+
+```ruby
 my_hash.select do |key, value|
   value > 10
 end

notes/language/ruby/library/csv.md

@@ -0,0 +1,16 @@
+---
+title: CSV
+ref: https://ruby.github.io/csv/
+---
+
+## Usage
+
+Library that provides an interface to CSV files and data.
+
+```rb
+require 'csv'
+
+CSV.foreach('path/to/file.csv', headers: true) do |row|
+  puts row['name']
+end
+```

notes/language/ruby/library/http.md

@@ -3,9 +3,12 @@ title: Net::HTTP
 ref: https://docs.ruby-lang.org/en/3.4/Net/HTTP.html
 ---
 
-## Basic
+## Usage
+
+Library to make HTTP requests.
 
 ```ruby
 require 'net/http'
+
 Net::HTTP.get('example.com', '/index.html')
 ```

notes/language/ruby/library/json.md

@@ -0,0 +1,29 @@
+---
+title: JSON
+ref: https://docs.ruby-lang.org/en/3.4/JSON.html
+---
+
+## Usage
+
+Library to generate or parse JSON.
+
+```ruby
+require 'json'
+```
+
+Ruby object to JSON:
+
+```ruby
+my_hash = {
+  'name' => 'Taro',
+  'age' => 24,
+}
+json_str = my_hash.to_json
+json_str = JSON.generate(my_hash)
+```
+
+JSON to ruby object:
+
+```ruby
+my_hash = JSON.parse(json_str)
+```

notes/language/ruby/loop.md

@@ -0,0 +1,11 @@
+---
+title: Numbers
+ref: https://docs.ruby-lang.org/en/3.4/Numeric.html
+---
+
+## Methods
+
+| Method  | Description     |
+| ------- | --------------- |
+| `next`  | Increment by 1. |
+| `floor` | Round down.     |