ROR by Nguyen Huu Long

From Japan

longmentor — 2023-02-11 03:11:16 UTC

longmentor — 2023-02-11 03:12:46 UTC

3.times do
  print 'Welcome '
end

5.times { print "Odelay! " }

5.times { |time|
  puts time
}
-----
0
1
2
3
4

.reverse

longmentor — 2023-02-11 03:25:05 UTC

.length

longmentor — 2023-02-11 03:25:12 UTC

.to_s -> tostring

longmentor — 2023-02-11 03:26:37 UTC

.to_i

longmentor — 2023-02-11 03:27:04 UTC

.to_a

longmentor — 2023-02-11 03:27:12 UTC

.max

longmentor — 2023-02-11 03:28:33 UTC

.sort!

longmentor — 2023-02-11 03:32:07 UTC

they alter the variable for good use !

.gsub like .replace

longmentor — 2023-02-11 03:36:49 UTC

poem.reverse to reverse all

longmentor — 2023-02-11 03:37:56 UTC

poem.lines.reverse

longmentor — 2023-02-11 03:38:00 UTC

puts poem.lines.reverse.join

longmentor — 2023-02-11 03:38:45 UTC

book={}

longmentor — 2023-02-11 03:45:33 UTC

books["The deep end"] = :abysmal
puts books
"The deep end"=>"abysmal"
puts books.length
3
puts books["The deep end"]
abysmal
books.keys show all key
books.values show all value

Harsh Khắc nghiệt

longmentor — 2023-02-11 03:58:07 UTC

ratings = Hash.new {0}

books.values.each { |rate|
ratings[rate] += 1
}
puts books.values
puts ratings

------------
splendid
abysmal
mediocre
mediocre
{"splendid"=>1, "abysmal"=>1, "mediocre"=>2}

longmentor — 2023-02-11 04:30:00 UTC

def count_plays(year)
s = get_shakey

s["William Shakespeare"]
.select { |k, v|
v["finished"] == year
}.each { |key, val|
puts val["title"]
}.count
end

puts count_plays(1591)

longmentor — 2023-02-11 04:31:29 UTC

def print_plays(year_from, year_to)
get_shakey["William Shakespeare"]
.select { |k, v|
year_from <= v["finished"] &&
year_to >= v["finished"]
}.each { |k, v|
puts "#{v["title"].ljust(30)} #{v["finished"]}"
}
end
print_plays(1600, 1605)

https://try.ruby-lang.org/

longmentor — 2023-02-11 04:31:40 UTC

longmentor — 2023-02-11 04:34:18 UTC

5     <= 10     # => true
'abc' == 'def'  # => false
true            # => true
123456          # => true
0               # => true
nil             # => false
'xyz'.empty?    # => false
'a' > 5         # => error:
                # comparison of String with
                # Numeric failed

= # ==

longmentor — 2023-02-11 04:36:01 UTC

if else

longmentor — 2023-02-11 04:37:18 UTC

if elseif else

longmentor — 2023-02-11 04:37:26 UTC

attr_reader

longmentor — 2023-02-11 05:02:06 UTC

attr_writer

longmentor — 2023-02-11 05:02:21 UTC

attr_accessor

longmentor — 2023-02-11 05:02:36 UTC

@content = content[0..39]

longmentor — 2023-02-11 07:00:18 UTC

@variable Object variable

longmentor — 2023-02-11 07:11:03 UTC

longmentor — 2023-02-11 07:37:37 UTC

class Blurb
  attr_accessor :content, :time, :mood

  def initialize(mood, content="")
    @time    = Time.now
    @content = content[0..39]
    @mood    = mood
  end

  def moodify
    if    @mood == :sad
      return ":-("
    elsif @mood == :happy
      return ":-)"
    # Add other moods here
    end

    # The default mood
    ":-|"
  end
end

class Blurbalizer
  def initialize(title)
    @title  = title
    @blurbs = []
  end

  def add_a_blurb(mood, content)
    @blurbs << Blurb.new(mood, content)
  end

  def show_timeline
    puts "Blurbalizer: #{@title} has #{@blurbs.count} Blurbs"

    @blurbs.sort_by { |t|
      t.time
    }.reverse.each { |t|
      puts "#{t.content.ljust(40)} #{t.mood} #{t.time}"
    }
  end
end
myapp = Blurbalizer.new "The Big Blurb"
myapp.add_a_blurb(:happy,"okokok")
myapp.add_a_blurb(:sad,"not okokok")

myapp.show_timeline

Matz

longmentor — 2023-02-11 07:53:15 UTC

longmentor — 2023-02-11 07:56:14 UTC

# I am a single line comment.

=begin

I am a multi line comment. I can take as many lines as needed.

=end

longmentor — 2023-02-11 07:56:52 UTC

# Integer 
valuex = 1

# Float 
valuey = 1.2

longmentor — 2023-02-11 07:58:13 UTC

puts "codecademy".upcase# CODECADEMY

puts "Codecademy".downcase# codecademy

longmentor — 2023-02-11 07:59:09 UTC

age = 30

print "Hi, my name is Cody, and I am #{age} years old"# "Hi, my name is Cody, and I am 30 years old"

longmentor — 2023-02-11 08:00:33 UTC

print "Type your name and press Enter: "name = gets.chomp

puts "My name is #{name}!"

longmentor — 2023-02-11 08:08:05 UTC

print "Enter a number"

number = gets.to_i
unless number > 10  
puts "number is less than 10."
end

longmentor — 2023-02-11 08:10:50 UTC

data = [3, 6, 9, 12]

data.each do |num|  
puts "The number is: #{num}"
end

longmentor — 2023-02-11 08:12:22 UTC

for i in 1..10  
next if i % 2 == 0  
puts i
end

longmentor — 2023-02-11 08:13:26 UTC

i = 1

while i <= 3 do  
puts "Message number #{i}"  
i = i + 1
end

longmentor — 2023-02-11 08:16:44 UTC

# Inclusive
(3..5).each do |i|  
puts i
end# Output:
# 3
# 4
# 5

# Exclusive
(3...5).each do |i|  
puts i
end
# Output
# 3
# 4

longmentor — 2023-02-11 08:19:06 UTC

num = 1

loop do  
puts "We are in the loop!"  
num += 1  
break if num > 3
end
puts "We have exited the loop!"

longmentor — 2023-02-11 08:20:23 UTC

i = 1

until i == 4 do  
puts "Message number #{i}"  
i = i + 1
end

longmentor — 2023-02-11 08:23:42 UTC

for i in 1..3 do  
puts "Message number #{i}"
end

longmentor — 2023-02-11 08:37:16 UTC

salary = {  "starting" => 40000}

salary["mid-level"] = 60000

longmentor — 2023-02-11 08:38:37 UTC

multi_array = [[0,1,2,3],[4.5, true, "hi"]]

# Accessing the array at index 1
puts multi_array[1] # => [4.5, true, "hi"]

# Accessing the element at index 0 within the array at index 1
puts multi_array[1][0] # => 4.5

longmentor — 2023-02-11 08:49:51 UTC

puts "Keanu" <=> "Adrianna" 
# The first letters of each word are compared in ASCII order and since "K" comes after "A", 1 is printed.

puts 1 <=> 2 # -1

puts 3 <=> 3 # 0

#<=> can also be used inside of a block and to sort values in descending order:
my_array = [3, 0, 8, 7, 1, 6, 5, 9,4]
my_array.sort! { |first_num, second_num| second_num <=> first_num }
print my_array
#Output => [9, 8, 7, 6, 5, 4, 3, 1, 0]

longmentor — 2023-02-11 08:54:02 UTC

def extra_curriculars(*clubs)  
clubs.each { |club| puts "After school, I'm involved with #{club}" }
end

extra_curriculars("chess club", "gymnastics", "anime club", "library services")

longmentor — 2023-02-11 08:57:38 UTC

my_bologna = {  
:first_name => "Oscar",  
:second_name => "Meyer",  
:slices => 12}

puts my_bologna[:second_name] # => Meyer

longmentor — 2023-02-11 08:59:28 UTC

olympic_trials = {  Sally: 9.58,  John: 9.69,  Bob: 14.91}

olympic_trials.select { |name, time| time <  10.05 }

longmentor — 2023-02-11 09:00:46 UTC

eren_jaeger = {  
age: 15,  
enemy: "titans",  
branch: "Survey Corps"
}
eren_jaeger.each_key { |key| puts key }
eren_jaeger.each_value { |value| puts value }

longmentor — 2023-02-11 09:03:52 UTC

tv_show = "Bob's Burgers"

case tv_show  when "Archer"    
puts "I don't like the voice of Archer."  
when "Bob's Burgers"    
puts "I love the voice of Bob Belcher."  
else    
puts "I don't know who voices this cartoon."

end

longmentor — 2023-02-11 09:09:18 UTC

puts "A".respond_to?(:push)
# => false
puts "A".respond_to?(:next)
# => true

longmentor — 2023-02-11 09:20:26 UTC

a = true

b = false

c = true

puts a || b

#Output => true

puts b || a

#Output => true

puts a && c

#Output => true 

puts a && b

#Output => false

longmentor — 2023-02-11 09:20:42 UTC

a = true
b = false
c = true

puts a || b
#Output => true
puts b || a
#Output => true
puts a && c
#Output => true 
puts a && b
#Output => false

longmentor — 2023-02-11 09:22:02 UTC


"B".upto("F") { |letter| print letter, " " }# => B C D E F

5.downto(0) { |num| print num, " " }# => 5 4 3 2 1 0

longmentor — 2023-02-11 09:23:45 UTC

boyfriend = nil #OR FALSE

boyfriend ||= "Jimmy Jr."

boyfriend ||= "Josh"

puts boyfriend# => "Jimmy Jr."

longmentor — 2023-02-11 09:24:43 UTC


array = [1, 2, 3]array << 4print array#Output => [1, 2, 3, 4]

puts "Hello," << " welcome to Codecademy."#Output => Hello, welcome to Codecademy.

longmentor — 2023-02-11 09:26:21 UTC

puts "This number is even!" if num % 2 == 0

longmentor — 2023-02-11 09:29:01 UTC


proc_test = Proc.new { puts "I am the proc method!" }lambda_test = lambda { puts "I am the lambda method!"}

proc_test.call # => I am the proc method!lambda_test.call # => I am the lambda method!

longmentor — 2023-02-11 09:32:49 UTC

def proc_demo_method  
proc_demo = Proc.new { return "Only I print!" }  
proc_demo.call  "But what about me?" 
# Never reachedend

puts proc_demo_method 

# Output # Only I print!

def lambda_demo_method  
lambda_demo = lambda { return "Will I print?" }  lambda_demo.call  "Sorry - it's me that's printed."

end

puts lambda_demo_method

# Output

# Sorry - it's me that's printed.

longmentor — 2023-02-11 09:33:05 UTC

def proc_demo_method  
proc_demo = Proc.new { return "Only I print!" }  
proc_demo.call  "But what about me?" 
# Never reachedend

puts proc_demo_method 
# Output # Only I print!

def lambda_demo_method  
lambda_demo = lambda { return "Will I print?" }  lambda_demo.call  "Sorry - it's me that's printed."
end

puts lambda_demo_method
# Output
# Sorry - it's me that's printed.

longmentor — 2023-02-11 09:33:52 UTC

first_arr = [3, 4, 5]
second_arr = first_arr.collect { |num| num * 5 }

print second_arr 
#Output => [15, 20, 25]

longmentor — 2023-02-11 09:34:30 UTC

def yield_test  
puts "I'm inside the method."  
yield
puts "I'm also inside the method."end

yield_test { puts ">>> I'm butting into the method!" }
#Output
# I'm inside the method.
# >>> I'm butting into the method.
# I'm also inside the method.

longmentor — 2023-02-11 09:38:25 UTC

square = Proc.new { |x| x ** 2 }

puts [2, 4, 6].collect!(&square)
# => [4, 16, 36]

longmentor — 2023-02-11 09:47:26 UTC

class Trip  
def initialize(duration, price)    
@duration = duration    
@price = price  endend

class Cruise < Trip  
def initialize(duration, price)    
super  
end

end

spain_backpacking = Trip.new(14, 800.00)carnival = Cruise.new(7, 2400.00)

longmentor — 2023-02-11 09:47:48 UTC

class Trip  
def initialize(duration, price)    
@duration = duration    
@price = price  endend

class Cruise < Trip  
   def initialize(duration, price)    
   super  
   end
end

spain_backpacking = Trip.new(14, 800.00)carnival = Cruise.new(7, 2400.00)

longmentor — 2023-02-11 09:54:31 UTC

puts Math::PI# => 3.141592653589793

longmentor — 2023-02-11 09:56:33 UTC

require 'date'

puts Date.today# => 2020-04-16

longmentor — 2023-02-11 10:00:44 UTC

module MyPizza  
FAVE_TOPPING = "Buffalo Chicken"
end

longmentor — 2023-02-11 10:19:19 UTC

https://www.codecademy.com/learn/learn-ruby/modules/learn-ruby-introduction-to-ruby-u/cheatsheet

longmentor — 2023-02-11 10:51:11 UTC

aFile = File.new("filename", "mode")
   # ... process the file
aFile.close

longmentor — 2023-02-11 10:51:25 UTC

File.open("filename", "mode") do |aFile|
   # ... process the file
end

sysread

longmentor — 2023-02-11 10:52:54 UTC

aFile = File.new("input.txt", "r")
if aFile
   content = aFile.sysread(20)
   puts content
else
   puts "Unable to open file!"
end

syswrite

longmentor — 2023-02-11 10:53:16 UTC

aFile = File.new("input.txt", "r+")
if aFile
   aFile.syswrite("ABCDEF")
else
   puts "Unable to open file!"
end

each_byte

longmentor — 2023-02-11 10:54:37 UTC

aFile = File.new("input.txt", "r+")
if aFile
   aFile.syswrite("ABCDEF")
   aFile.each_byte {|ch| putc ch; putc ?. }
else
   puts "Unable to open file!"
end

IO.readlines

longmentor — 2023-02-11 10:56:02 UTC

arr = IO.readlines("input.txt")
puts arr[0]
puts arr[1]

IO.foreach

longmentor — 2023-02-11 10:56:26 UTC

IO.foreach("input.txt"){|block| puts block}

longmentor — 2023-02-11 10:56:50 UTC

# Rename a file from test1.txt to test2.txt
File.rename( "test1.txt", "test2.txt" )

longmentor — 2023-02-11 10:57:12 UTC

# Delete file test2.txt
File.delete("test2.txt")

longmentor — 2023-02-11 10:58:02 UTC

file = File.new( "test.txt", "w" )
file.chmod( 0755 )

File Inquiries

longmentor — 2023-02-11 10:58:24 UTC

File.open("file.rb") if File::exists?( "file.rb" )

longmentor — 2023-02-11 10:59:06 UTC

# This returns either true or false
File.file?( "text.txt" )

longmentor — 2023-02-11 10:59:21 UTC

# a directory
File::directory?( "/usr/local/bin" ) # => true

# a file
File::directory?( "file.rb" ) # => false

longmentor — 2023-02-11 10:59:59 UTC

File.readable?( "test.txt" )   # => true
File.writable?( "test.txt" )   # => true
File.executable?( "test.txt" ) # => false

longmentor — 2023-02-11 11:00:19 UTC

File.zero?( "test.txt" )      # => true

longmentor — 2023-02-11 11:00:38 UTC

File.size?( "text.txt" )     # => 1002

longmentor — 2023-02-11 11:00:53 UTC

File::ftype( "test.txt" )     # => file

created, modified, or last accessed −

longmentor — 2023-02-11 11:01:59 UTC

File::ctime( "test.txt" ) # => Fri May 09 10:06:37 -0700 2008
File::mtime( "text.txt" ) # => Fri May 09 10:44:44 -0700 2008
File::atime( "text.txt" ) # => Fri May 09 10:45:01 -0700 2008

longmentor — 2023-02-11 11:03:42 UTC

Navigating Through Directories
Dir.chdir("/usr/bin")

puts Dir.pwd # This will return something like /usr/bin

list of the files and directories

longmentor — 2023-02-11 11:04:06 UTC

puts Dir.entries("/usr/bin").join(' ')

Dir.foreach("/usr/bin") do |entry|
   puts entry
end

Dir["/usr/bin/*"]

longmentor — 2023-02-11 11:06:07 UTC

Dir.mkdir("mynewdir")

Dir.mkdir( "mynewdir", 755 )

Dir.delete("testdir")

Creating Files & Temporary Directories

longmentor — 2023-02-11 11:06:17 UTC

require 'tmpdir'
   tempfilename = File.join(Dir.tmpdir, "tingtong")
   tempfile = File.new(tempfilename, "w")
   tempfile.puts "This is a temporary file"
   tempfile.close
   File.delete(tempfilename)

require 'tempfile'
   f = Tempfile.new('tingtong')
   f.puts "Hello"
   puts f.path
   f.close

longmentor — 2023-02-11 11:07:47 UTC

https://www.tutorialspoint.com/ruby/ruby_exceptions.htm