Find centralized, trusted content and collaborate around the technologies you use most.
Teams
Q&A for work
Connect and share knowledge within a single location that is structured and easy to search.
执行
filter(i -> !ismissing(i.dep_delay > 60), select(flights, (:carrier, :dep_delay)))
应该延迟超过 60 分钟(我的理解!)。但它返回所有正负 dep_delays 的运营商。
为什么它的行为如此?
我知道你更想写:
filter(i -> coalesce(i.dep_delay > 60, false), select(flights, (:carrier, :dep_delay)))
如果你写!ismissing(i.dep_delay > 60),你会得到trueif i.dep_delayis not missing。
!ismissing(i.dep_delay > 60)
true
i.dep_delay
missing