[R] duplicated() on zero-column data frames returns empty

[Ivan Krylov]

В Fri, 5 Apr 2024 16:08:13 +0000
Jorgen Harmse <JHarmse using roku.com> пишет:

> if duplicated really treated a row name as part of the row then
> any(duplicated(data.frame(…))) would always be FALSE. My expectation
> is that if key1 is a subset of key2 then all(duplicated(df[key1]) >=
> duplicated(df[key2])) should always be TRUE.

That's a good argument, thank you!

Would you suggest similar changes to duplicated.matrix too? Currently
it too returns 0-length output for 0-column inputs:

# 0-column matrix for 0-column input
str(duplicated(matrix(0, 5, 0)))
# logi[1:5, 0 ] 

# 1-column matrix for 1-column input
str(duplicated(matrix(0, 5, 1)))
# logi [1:5, 1] FALSE TRUE TRUE TRUE TRUE

# a dim-1 array for >1-column input
str(duplicated(matrix(0, 5, 10)))
# logi [1:5(1d)] FALSE TRUE TRUE TRUE TRUE

-- 
Best regards,
Ivan