Remove items from a list if they are not split between lists
Some sample data
List1 = list("Jake009", "Sarah0390", "Tom_338", "Philip-478")
List2 = list("Jake__98", "Sarah//43", "Brett-49")
I want to remove all items from a list that do not have a match in list 2.
So the code would have to check each line in both lists up to the first non-alphabetic character (like "Jake") and see if there is a match in the other list. If not, remove it from the list.
Purpose:
List1 = "Jake009", "Sarah0390"
List2 = "Jake__98", "Sarah//43"
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1 answer
We strip the non-alphabetic characters from sub
in lists
and use it %in%
to get the logical index of the elements present in one relative to the other.
v1 <- sub('[^A-Za-z]+$', '', unlist(List1))
v2 <- sub('[^A-Za-z]+$', '', unlist(List2))
List1[v1 %in% v2]
#[[1]]
#[1] "Jake009"
#[[2]]
#[1] "Sarah0390"
List2[v2 %in% v1]
#[[1]]
#[1] "Jake__98"
#[[2]]
#[1] "Sarah//43"
Or using intersect
as suggested by @Frank
vv1 <- setNames(List1,v1)
vv2 <- setNames(List2,v2)
both <- intersect(names(vv1),names(vv2))
vv1[both]
vv2[both]
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