Ruby 同样是 Range , 为啥后者没有 size ？
p (1..10).size
p ('a'..'z').size
其它语言也这样处理吗？
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lukertty
lukertty
[6] pry(main)> ("00:01".."12:34").to_a.size
=> 1234
其它语言应该都是这样吧？ https://play.crystal-lang.org/#/r/5ixe 可以统计一下
源码有注释，开头和结尾必须都是数字才返回 size
Both the begin and the end of the Range must be Numeric, otherwise nil is returned.
# rng.size -> num
#
# Returns the number of elements in the range. Both the begin and the end of
# the Range must be Numeric, otherwise nil is returned.
#
# (10..20).size #=> 11
# ('a'..'z').size #=> nil
# (-Float::INFINITY..Float::INFINITY).size #=> Infinity
def size()
#This is a stub, used for indexing
end