Ruby3 流程控制

if/else/elsif

a = 'hello' b = false  if a     p a elsif b     p b else     p 'ok' end

unless

unless相当于if的反向断言

unless false     'ok' end # => 'ok'

if/unless

a = 1 if a != 1 #如果a不是1 则a复制为1 b = 2 unless defined?(b) #如果b未定义 那么就定义b赋值为2

case

case a when 1     1 when /hello/     "hello world" when Array     [] else     'ok' end

while

a = 0 while a < 100 do     p a     a += 1 end

ruby 没有++和--操作符

Iterators

for x in [1, 2, 3] do     p x end  [1, 2, 2].each do |x|     p x end  10.times {|x| p x}