当a
未定义时,a || 1
会抛出错误,但a = a || 1
不会。是不是有点不协调?
irb(main):001:0> a
NameError: undefined local variable or method 'a' for main:Object
from (irb):1
from c:/ruby/bin/irb:12:in '<main>'
irb(main):002:0> a || 1
NameError: undefined local variable or method 'a' for main:Object
from (irb):2
from c:/ruby/bin/irb:12:in '<main>'
irb(main):003:0> a = a || 1
=> 1