Can't use zoo's as.yearmon properly, the transformed column has years showing up like 0086-CodePudding

Hello and thanks for being here.

I'm trying to convert dates with as.yearmon but the results I'm getting are odd and I do not know how to fix this; I tried searching on here and on the offical package guide without finding someone with the same problem. The problem is that I transformed a column of a dataset which was formatted as "month/year" with as.yearmon but the results were not correct.

For example, the first 3 values of the column of the original DF are: "1/86", "2/86", "3/86".

After using this function to convert them:

library(zoo)
Dates <- Returns
Dates$Month<- zoo::as.yearmon(Dates$Month, "%m / %Y")

[Where "Returns" is the original dataframe and Dates the new one with the modified dates.]

The result I got, instead of being: "gen 1986", "feb 1986", "mar 1986" was "gen 0086", "feb 0086", "mar 0086" and I don know why.

[I should not that "gen", "feb", "mar" are in Italian; I do not know if that matters and I do not know how to change that to "Jan", "Feb", "Mar" which I think I'll have to do as well]

Thanks in advance for your help, if something is not clear just let me know; I'm still a rookie.

CodePudding user response：

You need to use "%m/%y" instead of "%m/%Y". Your dates don't have a the full year notation.

x <- c("1/86", "2/86", "3/86")

zoo::as.yearmon(x, "%m/%y")
[1] "jan 1986" "feb 1986" "mrt 1986"

Date functions return the names in the local locale. If you want them in English:

Sys.setlocale("LC_TIME", "English")

zoo::as.yearmon(x, "%m/%y")
[1] "Jan 1986" "Feb 1986" "Mar 1986"

Everytime you restart R, this will be set back to your locale.

More info here on SO