一般语言中,函数必须有返回值,即要带个return关键字。但在ruby中,return不是必须的,如果不写会默认返回最终计算的结果。举例
def add(a,b) # 省去了return a + b end puts add 2,3
注意看下面的结果
def a puts "A was evaluated!" return true end def b puts "B was also evaluated!" return true end puts a || b puts "------" puts a && b
结果
A was evaluated! true ------ A was evaluated! B was also evaluated! true
|| 当 a为真就不执行b了
&& 若a为真还会继续执行b