I am trying to do the following:
subset_Portugal <- subset(data_frame, data_frame$iso_code == "PRT" & data_frame$date <= "2021-02-27" & data_frame$date >= "2020-04-01")
Works great on windows, but on Linux (a fresh install) I get the following error:
> subset_Portugal <- subset(data_frame, data_frame$iso_code == "PRT" & data_frame$date <= "2021-02-27" & data_frame$date >= "2020-04-01")
Warning messages:
1: In Ops.factor(data_frame$date, "2021-02-27") :
‘<=’ not meaningful for factors
2: In Ops.factor(data_frame$date, "2020-04-01") :
‘>=’ not meaningful for factors
Why is this happening on Linux? How may I fix it?