Ruby语法笔记

接受用户输入

first_name = gets.chomp

首字母大写

first_name.capitalize!

字母变大写

first_name.upcase!

字母变小写

first_name.downcase!

多行输出

print <<eof
  # 多行输出
eof

注释

# 我是注释

变量获取

#{first_name}

变量

1. 全局变量 $
2. 类变量 @@
3. 方法变量 @
4. 局部变量 小写字母或_
   

if/else

if a < b
  puts '1'
elsif b < a
  puts '2'
end    

类

class classname
  def functionname(params)
    puts params
  end
end

class1 = classname.new
class1.functionname('1')
unless
unless false
  print 'ok'
else
  print 'no'
end    

是否包含字符

print 'puts'

user_input = gets.chomp

user_input.downcase!

if user_input.include?"s"
  print 'has s'
end

替换字符

# s -> th
user_input.gsub!(/s/,"th")

在字符串中输出变量值

puts 'okok #{user_input}'

while

counter = 1

while counter < 11
  puts counter
  counter = counter + 1
end

until

counter = 1
until counter > 10
  print counter
  counter = counter + 1
end 
 

+= 、 -= 、 *=、 /=
some languages have the increment operators ++ and -- (which also add or subtract 1 from a value), but ruby does not
for循环
# 如果 1...10 包含1-9，如果 1..10 包含1-10

for num in 1...10
  puts num
end  

loop method
an iterator is just a ruby method that repeatedly invokes a block of code.

i = 20
loop do
  i -= 1
  print "#{ i }"
  break if i <= 0
end  

next

i = 20
loop do
 i -= 1
 next if i%2 != 0
 print "#{i}"
 break if i <= 0
end

数组

my_array = [1,2,3,4,5]

the .each iterator迭代器

numbers = [1, 2, 3, 4, 5]

# one way to loop
numbers.each { |item| puts item }

# another way to loop
numbers.each do |item|
 puts item
end

the .times iterator 次数迭代器

10.times { print 'ok'})

looping with 'while'

num = 1

while num <= 50 do
  print num
  num += 1
end  

looping with 'until'

num = 1
until num > 50 do
  print num
  num += 1
end  

loop the loop with loop

num = 0

loop do
  num += 1
  print "ruby!"
  break if num == 30
end  

the .split method,

text.split(",")

puts "text to search through: "
text = gets.chomp
puts "word to redact"
redact = gets.chomp

words = text.split(" ")

words.each do |word|
  print word
end