rtibbletime

Transformation of daily prices in monthly log returns


I'm trying to replicate a code from a book, "Reproducible Finance with R". All went quite good except for the following part.

asset_returns_tbltime <-
prices %>%
tk_tbl(preserve_index = TRUE,
rename_index = "date") %>%
as_tbl_time(index = date) %>%
as_period(period = "month",
side = "end") %>%
gather(asset, returns, -date) %>%
group_by(asset) %>%
tq_transmute(mutate_fun = periodReturn,
type = "log") %>%
spread(asset, monthly.returns) %>%
select(date, symbols)

That gives me the following error after the string tq_transmute(mutate_fun = periodReturn, type = "log") :

Error: Can't subset columns that don't exist. Column "asset" doesn't exist. Run rlang::last_error() to see where the error occurred. In addition: Warning message: "..." must not be empty for ungrouped data frames. Did you want data = everything()?

The data comes from the following code:

symbols <- c("SPY","EFA", "IJS", "EEM","AGG")
prices <-
getSymbols(symbols,
src = 'yahoo',
from = "2012-12-31",
auto.assign = TRUE,
warnings = FALSE) %>%
map(~Ad(get(.))) %>%
reduce(merge) %>%
`colnames<-`(symbols)

It would be nice if someone could point my attention towards the issue with the code (or with something else) as I think I've been lost.


Solution

  • If you use the updated pivot_longer and pivot_wider function instead of retired gather and spread this works.

    library(tidyverse)
    library(tibbletime)
    library(tidyquant)
    library(quantmod)
    
    prices %>%
      tk_tbl(preserve_index = TRUE,
             rename_index = "date") %>%
      as_tbl_time(index = date) %>%
      as_period(period = "month",
                side = "end") %>%
      pivot_longer(cols = -date, names_to = 'asset', values_to = 'returns') %>%
      group_by(asset) %>%
      tq_transmute(mutate_fun = periodReturn,
                   type = "log") %>%
      pivot_wider(names_from = asset, values_from = monthly.returns) %>%
      select(date, symbols)
    
    #   date           SPY     EFA      IJS      EEM       AGG
    #   <date>       <dbl>   <dbl>    <dbl>    <dbl>     <dbl>
    # 1 2012-12-31  0       0       0        0        0       
    # 2 2013-01-31  0.0499  0.0366  0.0521  -0.00294 -0.00623 
    # 3 2013-02-28  0.0127 -0.0130  0.0162  -0.0231   0.00589 
    # 4 2013-03-28  0.0373  0.0130  0.0403  -0.0102   0.000985
    # 5 2013-04-30  0.0190  0.0490  0.00122  0.0121   0.00964 
    # 6 2013-05-31  0.0233 -0.0307  0.0420  -0.0495  -0.0202  
    # 7 2013-06-28 -0.0134 -0.0271 -0.00140 -0.0547  -0.0158  
    # 8 2013-07-31  0.0504  0.0519  0.0635   0.0132   0.00269 
    # 9 2013-08-30 -0.0305 -0.0197 -0.0347  -0.0257  -0.00830 
    #10 2013-09-30  0.0312  0.0753  0.0639   0.0696   0.0111  
    # … with 94 more rows