greeting = 'Hello World!'
puts greeting
Hello World!
greeting = 'Hello World!'
print(greeting)
Hello World!
puts "Don't worry," + ' be happy'
Don't worry, be happy
print("Don't worry," + ' be happy')
Don't worry, be happy
first = "Don't worry,"
second = 'be happy'
puts "#{first} #{second}"
Don't worry, be happy
first = "Don't worry,"
second = 'be happy'
print('%s %s' % (first, second))
Don't worry, be happy[ 3.6 ]
first = "Don't worry,"
second = 'be happy'
print(f'{first} {second}')
puts 'This is not funny! I am not like him!'.gsub('not ', '')
This is funny! I am like him!
print('This is not funny! I am not like him!'.replace('not ', ''))
This is funny! I am like him!
puts 'You should work'.gsub('work', 'rest')
You should rest
print('You should work'.replace('work', 'rest'))
You should rest
puts 'I like beer'.split
I like beer
print('I like beer'.split())
['I', 'like', 'beer']
puts ' eh? '.strip
eh?
print(' eh? '.strip())
eh?
puts 'string' == 'string'
puts 'string' != 'string'
true false
print('string' == 'string')
print('string' != 'string')
True False
p 'apple' =~ /^b/
p 'apple' =~ /^a/
nil 0
import re
print(re.search('^b', 'apple'))
print(re.search('^a', 'apple'))
None <_sre.SRE_Match object; span=(0, 1), match='a'>
i = 9
i += 1
puts i
10
i = 9
i += 1
print(i)
10
puts 1 < 2 && 2 < 3
puts 5 == 5
puts 5 != 5
true true false
print(1 < 2 < 3)
print(5 == 5)
print(5 != 5)
True True False
puts rand(1..2)
1
import random
print(random.randint(1, 2))
1
puts 9 / 2
puts 9 / 2.0
puts (9 / 2.0).floor
puts (9 / 2.0).round
4 4.5 4 5
import math
print(9 // 2)
print(9 / 2)
print(math.floor(9 / 2))
print(round(9 / 2)) # rounds half to even
4 4.5 4 4
puts 'hi'.class
puts 1.class
String Fixnum
print(type('hi'))
print(type(1))
<class 'str'> <class 'int'>
puts 10.to_f
10.0
print(float(10))
10.0
puts 10.to_s
10
print(str(10))
10
puts '5'.to_i
5
print(int('5'))
5
puts '10'.is_a? String
true
print(isinstance('10', str))
True
def check(label, fn, values)
puts label
values.each do |value|
begin
result = fn.call(value) ? 'true' : 'false'
rescue NoMethodError => e
result = "error: #{e}"
end
puts format(" %-9p - %s", value, result)
end
puts ''
end
values = ['string', '', [1, 2, 3], [], 5, 0, true, false, nil]
check('if value:', -> (v) { v }, values)
check('if value.nil?:', -> (v) { v.nil? }, values)
check('if value.empty?:', -> (v) { v.empty? }, values)
if value: "string" - true "" - true [1, 2, 3] - true [] - true 5 - true 0 - true true - true false - false nil - false if value.nil?: "string" - false "" - false [1, 2, 3] - false [] - false 5 - false 0 - false true - false false - false nil - true if value.empty?: "string" - false "" - true [1, 2, 3] - false [] - true 5 - error: undefined method `empty?' for 5:Fixnum 0 - error: undefined method `empty?' for 0:Fixnum true - error: undefined method `empty?' for true:TrueClass false - error: undefined method `empty?' for false:FalseClass nil - error: undefined method `empty?' for nil:NilClass
def check(label, fn, values):
print(label)
for value in values:
try:
result = 'true' if fn(value) else 'false'
except TypeError as e:
result = 'error: %s' % e
print(" %-9r - %s" % (value, result))
print()
values = ['string', '', [1, 2, 3], [], 5, 0, True, False, None]
check('if value:', lambda v: v, values)
check('if value is None:', lambda v: v is None, values)
check('if len(value):', lambda v: len(v), values)
if value: 'string' - true '' - false [1, 2, 3] - true [] - false 5 - true 0 - false True - true False - false None - false if value is None: 'string' - false '' - false [1, 2, 3] - false [] - false 5 - false 0 - false True - false False - false None - true if len(value): 'string' - true '' - false [1, 2, 3] - true [] - false 5 - error: object of type 'int' has no len() 0 - error: object of type 'int' has no len() True - error: object of type 'bool' has no len() False - error: object of type 'bool' has no len() None - error: object of type 'NoneType' has no len()
arr = %w(first second)
puts arr
first second
arr = ['first', 'second']
print(arr)
['first', 'second']
arr = []
arr.push 'first'
arr.push 'second'
puts arr
first second
arr = []
arr.append('first')
arr.append('second')
print(arr)
['first', 'second']
puts ['first', 1]
first 1
print(['first', 1])
['first', 1]
puts [1, 2].include? 1
true
print(1 in [1, 2])
True
[1, 2].each do |num|
puts num
end
1 2
for num in [1, 2]:
print(num)
1 2
%w(one two).each_with_index do |num, i|
puts num
puts i
end
one 0 two 1
for i, num in enumerate(['one', 'two']):
print(num)
print(i)
one 0 two 1
arr = %w(one two)
puts arr.first
puts arr.last
one two
arr = ['one', 'two']
print(arr[0])
print(arr[-1])
one two
arr = [1, 5, 10, 20]
puts arr.find(&:even?)
10
arr = [1, 5, 10, 20]
print(next(i for i in arr if i % 2 == 0))
10
arr = [1, 5, 10, 20]
puts arr.select(&:even?)
10 20
arr = [1, 5, 10, 20]
print([i for i in arr if i % 2 == 0])
[10, 20]
arr = [1, 5, 10, 20]
puts arr.map { |num| num * 2 }
2 10 20 40
arr = [1, 5, 10, 20]
print([num * 2 for num in arr])
[2, 10, 20, 40]
puts [1, 2] + [3, 4]
1 2 3 4
print([1, 2] + [3, 4])
[1, 2, 3, 4]
puts [4, 2, 3, 1].sort
1 2 3 4
print(sorted([4, 2, 3, 1]))
[1, 2, 3, 4]
multi = [%w(first second), %w(third forth)]
puts multi[1][1]
forth
multi = [['first', 'second'], ['third', 'forth']]
print(multi[1][1])
forth
puts [1, 2, 3].size
3
print(len([1, 2, 3]))
3
arr = [1, 11, 111]
puts arr.count { |i| i > 10 }
2
arr = [1, 11, 111]
print(sum(1 for i in arr if i > 10))
2
puts [1, 2, 3].reduce(:+)
6
import functools, operator
print(functools.reduce(operator.add, [1, 2, 3]))
print(sum([1, 2, 3])) # a more Pythonic example
6 6
puts ['a', 'b', 'c'].index('c')
2
print(['a', 'b', 'c'].index('c'))
2
arr = %w(a b c)
arr.delete('b')
puts arr
a c
arr = ['a', 'b', 'c']
arr.remove('b')
print(arr)
['a', 'c']
puts %w(a b a).uniq
a b
print(set(['a', 'b', 'a']))
{'a', 'b'}
options = { font_size: 10, font_family: 'Arial' }
puts options
{:font_size=>10, :font_family=>"Arial"}
options = {'font_size': 10, 'font_family': 'Arial'}
print(options)
{'font_size': 10, 'font_family': 'Arial'}
options = {}
options[:font_size] = 10
options[:font_family] = 'Arial'
puts options
{:font_size=>10, :font_family=>"Arial"}
options = {}
options['font_size'] = 10
options['font_family'] = 'Arial'
print(options)
{'font_family': 'Arial', 'font_size': 10}
{ font_size: 10, font_family: 'Arial' }.each do |key, value|
puts key, value
end
font_size 10 font_family Arial
for key, value in {'font_size': 10, 'font_family': 'Arial'}.items():
print(key, value)
font_family Arial font_size 10
options = { font_size: 10, font_family: 'Arial' }
puts options.include? :font_size
true
options = {'font_size': 10, 'font_family': 'Arial'}
print('font_size' in options)
True
options = { font_size: 10, font_family: 'Arial' }
puts options[:font_size]
10
options = {'font_size': 10, 'font_family': 'Arial'}
print(options['font_size'])
10
options = { font_size: 10, font_family: 'Arial' }
puts options.size
2
options = {'font_size': 10, 'font_family': 'Arial'}
print(len(options))
2
try_it = true
puts 'Garlic gum is not funny' if try_it
Garlic gum is not funny
try_it = True
if try_it:
print('Garlic gum is not funny')
Garlic gum is not funny
COST = 100
COST = 50
puts COST
/Users/evmorov/projects/lang-compare/code/ruby/other_structure_constant.rb:2: warning: already initialized constant COST /Users/evmorov/projects/lang-compare/code/ruby/other_structure_constant.rb:1: warning: previous definition of COST was here 50
COST = 100
COST = 50
print(COST)
50
module Colors
RED = '#FF0000'
GREEN = '#00FF00'
end
puts Colors::GREEN
#00FF00
class Colors:
RED = '#FF0000'
GREEN = '#00FF00'
print(Colors.GREEN)
#00FF00
Customer = Struct.new(:name, :address) do
def greeting
"Hello #{name}!"
end
end
puts Customer.new('Dave', '123 Main').greeting
Hello Dave!
import collections
class Customer(collections.namedtuple('Customer', 'name address')):
def greeting(self):
return "Hello %s!" % self.name
print(Customer('Dave', '123 Main').greeting())
Hello Dave!
puts 'Hello' if true
Hello
if True:
print('Hello')
Hello
angry = false
puts 'smile!' unless angry
smile!
angry = False
if not angry:
print('smile!')
smile!
if true
puts 'work'
else
puts 'sleep'
end
work
if True:
print('work')
else:
print('sleep')
work
puts 'no' if true && false
puts 'yes' if true || false
yes
if True and False:
print('no')
if True or False:
print('yes')
yes
foo = 'Hello!'
case foo
when 1..5
puts "It's between 1 and 5"
when 10, 20
puts '10 or 20'
when 'And' then puts 'case in one line'
when String
puts "You passed a string '#{foo}'"
else
puts "You gave me '#{foo}'"
end
You passed a string 'Hello!'
foo = 'Hello!'
if foo in range(1, 6):
print("It's between 1 and 5")
elif foo in (10, 20):
print('10 or 20')
elif foo == 'And':
print('case in one line')
elif isinstance(foo, str):
print("You passed a string %r" % foo)
else:
print("You gave me %r" % foo)
You passed a string 'Hello!'
score = 76
grade = case
when score < 60 then 'F'
when score < 70 then 'D'
when score < 80 then 'C'
when score < 90 then 'B'
else 'A'
end
puts grade
C
score = 76
grades = [
(60, 'F'),
(70, 'D'),
(80, 'C'),
(90, 'B'),
]
print(next((g for x, g in grades if score < x), 'A'))
C
puts false ? 'no' : 'yes'
yes
print('no' if False else 'yes')
yes
result =
if true
'a'
else
'b'
end
puts result
a
result = 'a' if True else 'b'
print(result)
a
(1..3).each do |i|
puts "#{i}. Hi"
end
1. Hi 2. Hi 3. Hi
for i in range(1, 4):
print('%d. Hi' % i)
1. Hi 2. Hi 3. Hi
(0..4).step(2) do |i|
puts i
end
0 2 4
for i in range(0, 5, 2):
print(i)
0 2 4
3.times do
puts 'Hi'
end
Hi Hi Hi
for i in range(3):
print('Hi')
Hi Hi Hi
i = 0
while i < 3
i += 1
end
puts i
3
i = 0
while i < 3:
i += 1
print(i)
3
i = 0
i += 1 until i == 3
puts i
3
i = 0
while i != 3:
i += 1
print(i)
3
greetings = Array.new(3) do |i|
"#{i + 1}. Hello!"
end
puts greetings
1. Hello! 2. Hello! 3. Hello!
greetings = ["%d. Hello!" % time for time in range(1, 4)]
print(greetings)
['1. Hello!', '2. Hello!', '3. Hello!']
3.times do |time|
puts "#{time + 1}. Hi"
break if time == 1
end
1. Hi 2. Hi
for time in range(1, 4):
print("%d. Hi" % time)
if time == 2:
break
1. Hi 2. Hi
3.times do |time|
next if time == 1
puts "#{time + 1}. Hi"
end
1. Hi 3. Hi
for time in range(1, 4):
if time == 2:
continue
print("%d. Hi" % time)
1. Hi 3. Hi
arr = [1, 2, 3]
puts arr.min
puts arr.max
1 3
arr = [1, 2, 3]
print(min(arr))
print(max(arr))
1 3
puts Math.sqrt(9)
3.0
import math
print(math.sqrt(9))
3.0
begin
1 / 0
rescue
puts "Can't divide"
ensure
puts "But that's ok"
end
1 / 0 rescue puts "Can't divide"
Can't divide But that's ok Can't divide
try:
1 / 0
except:
print("Can't divide")
finally:
print("But that's ok")
Can't divide But that's ok
begin
1 / 0
rescue => e
puts e.message
end
divided by 0
try:
1 / 0
except Exception as e:
print(e)
division by zero
def divide(num1, num2)
num1 / num2
rescue => e
puts e.message
end
divide(1, 0)
divided by 0
def divide(num1, num2):
try:
num1 / num2
except Exception as e:
print(e)
divide(1, 0)
division by zero
begin
fail 'An error!'
rescue => e
puts e.message
end
An error!
try:
raise Exception('An error!')
except Exception as e:
print(e)
An error!
file_path = File.join(Dir.getwd, 'code', 'file.txt')
puts File.read(file_path)
Hello World
import os
with open(os.path.join(os.getcwd(), 'code', 'file.txt')) as f:
print(f.read())
Hello World
file_path = File.join(File.dirname(__FILE__), 'output.txt')
File.write(file_path, 'Some glorious content')
import pathlib
with (pathlib.Path(__file__).parent / 'output.txt').open('w') as f:
f.write('Some glorious content')
puts Dir.getwd
/Users/evmorov/projects/lang-compare
import os
print(os.getcwd())
/Users/evmorov/projects/lang-compare
puts __FILE__
/Users/evmorov/projects/lang-compare/code/ruby/file_path.rb
print(__file__)
/Users/evmorov/projects/lang-compare/code/python/file_path.py
puts File.dirname(__FILE__)
/Users/evmorov/projects/lang-compare/code/ruby
import pathlib
print(pathlib.Path(__file__).parent)
/Users/evmorov/projects/lang-compare/code/python
puts File.expand_path File.join(__FILE__, '..', '..')
/Users/evmorov/projects/lang-compare/code
import pathlib
print(pathlib.Path(__file__).parents[1])
/Users/evmorov/projects/lang-compare/code
puts File.expand_path File.join(__FILE__, '..', '..', 'php')
/Users/evmorov/projects/lang-compare/code/php
import pathlib
print(pathlib.Path(__file__).parents[1] / 'ruby')
/Users/evmorov/projects/lang-compare/code/ruby
def hey
puts 'How are you?'
end
hey
How are you?
def hey():
print('How are you?')
hey()
How are you?
def sweets(buy, *brands)
puts brands if buy
end
sweets true, 'snickers', 'twix', 'bounty'
snickers twix bounty
def sweets(buy, *brands):
if buy:
print(brands)
sweets(True, 'snickers', 'twix', 'bounty')
('snickers', 'twix', 'bounty')
def send(abroad = false)
puts abroad ? 'Send abroad' : 'Send locally'
end
send
send true
Send locally Send abroad
def send(abroad=False):
print('Send abroad' if abroad else 'Send locally')
send()
send(True)
Send locally Send abroad
def multiple(a, b)
a * b
end
puts multiple(2, 3)
def divide(a, b)
return 0 if a == 0
a / b
end
puts divide 0, 10
def default_value
end
p default_value
6 0 nil
def multiply(a, b):
return a * b
def divide(a, b):
return 0 if a == 0 else a / b
def default_value():
pass
print(multiply(2, 3))
print(divide(0, 10))
print(default_value())
6 0 None
square = -> (x) { x * x }
puts [2, 3].map(&square)
greeting = -> { puts 'Hello World!' }
greeting.call
4 9 Hello World!
square = lambda x: x * x
print(list(map(square, [2, 3])))
greeting = lambda: print('Hello World!')
greeting()
[4, 9] Hello World!
def my_select(arr)
selected = []
arr.each do |a|
selected.push a if yield(a)
end
selected
end
puts my_select [1, 5, 10] { |x| x < 6 }
def my_select(arr, &filter)
selected = []
arr.each do |a|
selected.push a if filter.call(a)
end
selected
end
puts my_select [1, 5, 10] { |x| x < 6 }
1 5 1 5
def select(arr):
yield from arr
def select_filter(arr, filter):
for a in arr:
if filter(a):
yield a
print([x for x in select([1, 5, 10]) if x < 6])
print(list(select_filter([1, 5, 10], lambda x: x < 6)))
[1, 5] [1, 5]
class Action
def self.say(&sentence)
@name = 'Ann'
puts sentence.call
end
end
class Person
def initialize(name)
@name = name
end
def greet
Action.say { "My name is #{@name}!" }
end
end
Person.new('Alex').greet
My name is Alex!
class Action:
name = 'Ann'
@staticmethod
def say(sentence):
print(sentence())
class Person:
def __init__(self, name):
self.name = name
def greet(self):
Action.say(lambda: "My name is %s!" % self.name)
Person('Alex').greet()
My name is Alex!
class ProccessElements
def self.element(el_name)
define_method "#{el_name}_element" do |content|
"<#{el_name}>#{content}</#{el_name}>"
end
end
end
class HtmlELements < ProccessElements
element :div
element :span
end
puts HtmlELements.new.div_element('hello')
<div>hello</div>
class ProccessElements:
def __init__(self):
def element(el_name):
def render(content):
return '<{0}>{1}</{0}>'.format(el_name, content)
return render
for el_name in self.elements:
setattr(self, el_name, element(el_name))
class HtmlELements(ProccessElements):
elements = ('div', 'span')
print(HtmlELements().div('hello'))
<div>hello</div>
class Greetings
def hey
puts 'How are you?'
end
alias_method :hi, :hey
end
Greetings.new.hi
How are you?
class Greetings:
def hey(self):
print('How are you?')
hi = hey
Greetings().hi()
How are you?
class Animal
def walk
puts "I'm walking"
end
end
Animal.new.walk
I'm walking
class Animal:
def walk(self):
print("I'm walking")
Animal().walk()
I'm walking
class Animal
def initialize(name)
@name = name
end
def walk
puts "My name is #{@name} and I'm walking"
end
end
Animal.new('Kelya').walk
My name is Kelya and I'm walking
class Animal:
def __init__(self, name):
self.name = name
def walk(self):
print("My name is %s and I'm walking" % self.name)
Animal('Kelya').walk()
My name is Kelya and I'm walking
class Animal
def walk
bark
guard
puts "I'm walking"
end
def bark
puts 'Wuf!'
end
private
def guard
puts 'WUUUF!'
end
end
Animal.new.walk
Wuf! WUUUF! I'm walking
class Animal:
def walk(self):
self.bark()
self._guard()
print("I'm walking")
def bark(self):
print('Wuf!')
# Private by convention
def _guard(self):
print('WUUUF!')
Animal().walk()
Wuf! WUUUF! I'm walking
class Animal
def self.feed
puts 'Om nom nom'
end
end
Animal.feed
Om nom nom
class Animal:
@classmethod
def feed(cls):
print('Om nom nom')
Animal.feed()
Om nom nom
class Animal
def eat(food)
puts 'Om nom nom' if meat? food
end
private
def meat?(food)
food == 'meat'
end
end
Animal.new.eat('meat')
Om nom nom
class Animal:
def eat(self, food):
if self._is_meat(food):
print('Om nom nom')
def _is_meat(self, food):
return food == 'meat'
Animal().eat('meat')
Om nom nom
class Animal
def initialize(name)
@name = name
greet
end
private
def greet
puts "Hello! My name is #{@name}"
end
end
Animal.new('Kelya')
Hello! My name is Kelya
class Animal:
def __init__(self, name):
self.name = name
self._greet()
def _greet(self):
print("Hello! My name is %s" % self.name)
Animal('Kelya')
Hello! My name is Kelya
class Animal
def take(toy)
@toy = toy
end
def play
puts "I'm playing with #{@toy}"
end
end
animal = Animal.new
animal.take('a ball')
animal.play
I'm playing with a ball
class Animal:
def take(self, toy):
self.toy = toy
def play(self):
print("I'm playing with %s" % self.toy)
animal = Animal()
animal.take('a ball')
animal.play()
I'm playing with a ball
class Animal
attr_accessor :name
end
animal = Animal.new
animal.name = 'Kelya'
puts animal.name
Kelya
class Animal:
name = None
animal = Animal()
animal.name = 'Kelya'
print(animal.name)
Kelya
class Animal
def walk
puts "I'm walking"
end
end
class Dog < Animal
def sing
puts 'Bark!'
end
end
Dog.new.walk
I'm walking
class Animal:
def walk(self):
print("I'm walking")
class Dog(Animal):
def sing(self):
print('Bark!')
Dog().walk()
I'm walking
module Moving
def walk
puts "#{self.class.name} is walking"
end
end
module Interacting
def talk
puts "#{self.class.name} is talking"
end
end
class Human
include Moving
include Interacting
end
human = Human.new
human.walk
human.talk
Human is walking Human is talking
class Moving:
def walk(self):
print("%s is walking" % self.__class__.__name__)
class Interacting:
def talk(self):
print("%s is talking" % self.__class__.__name__)
class Human(Moving, Interacting):
pass
human = Human()
human.walk()
human.talk()
Human is walking Human is talking
class Animal
def walk
puts "I'm walking"
end
end
animal = Animal.new
puts animal.respond_to? :walk
true
class Animal:
def walk(self):
print("I'm walking")
animal = Animal()
print(hasattr(animal, 'walk'))
True
# it's a comment
# it's a comment
speed = 0
speed ||= 15
puts speed
0
speed = 0
speed = 15 if speed is None else speed
print(speed)
0
class Winner
attr_reader :address
def initialize
# @address = Address.new
end
end
class Address
attr_reader :zipcode
def initialize
@zipcode = 192187
end
end
zip = Winner.new.address&.zipcode
puts zip ? "Zipcode is #{zip}" : "No prize without zipcode"
No prize without zipcode
# other_file_to_import.rb
# class Import
# def initialize
# puts 'I am imported!'
# end
# end
require_relative 'other_file_to_import'
Import.new
I am imported!
# other_file_to_import.py
# class Import:
# def __init__(self):
# print('I am imported!')
import other_file_to_import
other_file_to_import.Import()
I am imported!
one, two = [1, 2]
puts one, two
1 2
one, two = 1, 2
print(one, two)
1 2
require 'date'
puts Date.today
2016-09-12
import datetime
print(datetime.date.today())
2016-09-12
puts Time.now
2016-09-12 22:51:17 +0300
import datetime
print(datetime.datetime.now())
2016-09-12 22:51:37.384449
angry = false
puts 'smile!' if !angry
smile!
angry = False
if not angry:
print('smile!')
smile!
yeti = nil
footprints = yeti || 'bear'
puts footprints
bear
yeti = None
footprints = yeti or 'bear'
print(footprints)
bear
puts `ruby -v`
ruby 2.3.1p112 (2016-04-26 revision 54768) [x86_64-darwin15]
import subprocess
subprocess.call(['python3', '--version'])
Python 3.5.2