Pfthb

I did the following code to import a excel file in Rstudio:

(nms <- names(read_excel("myexcelfile.xlsx")))
(ct <- ifelse(grepl("^Date", nms), "text", "numeric"))
read_excel("myexcelfile.xlsx", col_types = ct)[-c(6:495),-c(3:71)]

The resul is this dataframe below:

structure(list(Data = c("41731", "41730", "41729", "41726", "41725"
), ABEV3 = c(15.2, 14.9, 15.22, 15.15, 15.18)), row.names = c(NA, 
-5L), class = c("tbl_df", "tbl", "data.frame"))

The first column should be the dates (Brazilian Format: Day/Month/Year).

How can I fix this?

Try this:

(nms <- names(read_excel("myexcelfile.xlsx")))
(ct <- ifelse(grepl("^Date", nms), "date", "numeric"))
df <- read_excel("myexcelfile.xlsx", col_types = ct)[-c(6:495),-c(3:71)]

df$Date <- format(as.Date(as.character(df$Date)), "%d-%m-%Y")

Instead of importing as text, import it as date and then format it in the way described below (there I suppose that you will save the Excel in the df dataframe and that the column will be called Date, but adjust as needed).