R studio Could not find function "as.xts"

Question

I ran this line of code on R studio:

X <- as.xts(cad[,-1], order.by = cad$date)

cad is the name of my data. This is what the data head looks like:

date          cad
  <chr>       <dbl>
1) 04/01/2016  0.187
2) 05/01/2016 -0.449

and this is the error I'm getting.

Error in as.xts(cad[, -1], order.by = cad$date) : 
  could not find function "as.xts"

Here are a few of the libraries I loaded: library(biwavelet) library(xts) library(ggplot2) require(biwavelet)

Can someone please help?