is.numeric(NA)
is.numeric(as.numeric(NA)
)
inp= a
inp= "a"
inp <- inp[!is.na(inp)]
inp
!is.na(inp)
is.na(inp)
inp
gsub(pattern = (/D)), replacement= 3)
gsub(pattern = ("[/D)"), replacement= 3)
gsub(pattern = inp("[/D)"), replacement= 3)
list.files
list.files()