library(xts)
data_ts <- xts(data,order.by = as.Date(data$date))

head(data_ts)

> library(xts)
> data_ts <- xts(data,order.by = as.Date(data$date))
Error in data$date : object of type 'closure' is not subsettable
> data_ts <- xts(data,order.by = as.Date(data$date))
Error in data$date : object of type 'closure' is not subsettable
> head(data_ts)
Error in head(data_ts) : object 'data_ts' not found