问题
I have a list that looks something like this:
[["Local 7" 1 "say" "Say: Inspect Fences"] ["Local 7" 1 "do" "Do: Shepherd Cows"] ["Local 6" 1 "say" "Say: Shepherd Cows"] ["Local 6" 1 "do" "Do: Shepherd Cows"] ["Local 6" 2 "say" "Say: Shepherd Cows"] ["Local 6" 2 "do" "Do: Shepherd Cows"] ["Local 7" 2 "say" "Say: Inspect Fences"] ["Local 7" 2 "do" "Do: Shepherd Cows"] ["Local 6" 3 "say" "Say: Shepherd Cows"] ["Local 6" 3 "do" "Do: Shepherd Cows"] ["Local 7" 3 "say" "Say: Inspect Fences"] ["Local 7" 3 "do" "Do: Inspect Fences"]]
I'd like to sort the list by item 1. (I know it already is in the copy/pasted version, but it might not always be.)
sort just returns an empty list (I'm not even sure why, but I guess that's a separate question), and sort-by doesn't seem to work because it needs a reporter that resolves to a boolean.
Is there a clever way to do this? Or would I need to first get a list of the values I want to sort by, then sort that, and then iterate over that list, creating a new list of the values in the original list in which the respective item value matches?
回答1:
Edit: Updated with NetLogo 6 syntax
You can convert this into a sort-by pretty easily:
to-report sort-with [ key lst ]
report sort-by [ [a b] -> (runresult key a) < (runresult key b) ] lst
end
Then you use it like so:
sort-with [ l -> item 1 l ] my-list
来源：https://stackoverflow.com/questions/31545569/sorting-list-of-lists-by-particular-index-of-inner-lists