I have a column in a dataframe, chr
and in the form "%Y-%m-%d %H:%M:%S"
. I have no problem converting them to POSIXct
. However, if I leave that column as chr
and after I use group_by
with that column as the first column of the new dataframe, I cannot convert that first column to POSIXct
any more
R says do not know how to convert 'abc[, 1]' to class “POSIXct”
. I check the structure of the new dataframe and the first column is still chr
. Really appreciate any help.