Ruby 这个算是 bug 么
a=[[1,2],[3,4]]
b=a.clone
b[0].delete_at(0)
p b #=>[[2],[3,4]]
p a #=>[[2],[3,4]]
ruby 1.9.3p484[i-386-mingwin32]
a=[[1,2],[3,4]]
b=a.clone
b[0].delete_at(0)
p b #=>[[2],[3,4]]
p a #=>[[2],[3,4]]
ruby 1.9.3p484[i-386-mingwin32]