Using `map ()` in a nested data frame

Question

I am having some problems using the map() function, as well as the nest() function.

I have some data configured as follows:

 counter counter date_time total 1 06032013 2013-06-03 16:00:00 476 2 06032013 2013-06-03 17:00:00 578 3 06032013 2013-06-03 18:00:00 406 4 06032013 2013-06-03 19:00:00 272 5 06032013 2013-06-03 20:00:00 240 6 06032013 2013-06-03 21:00:00 96 7 06032013 2013-06-03 22:00:00 67 8 06032013 2013-06-03 23:00:00 37 9 06032013 2013-06-04 00:00:00 10 10 06032013 2013-06-04 01:00:00 11 11 06032013 2013-06-04 02:00:00 8 12 06032013 2013-06-04 03:00:00 9 13 06032013 2013-06-04 04:00:00 23 14 06032013 2013-06-04 05:00:00 83 15 06032013 2013-06-04 06:00:00 291 16 06032013 2013-06-04 07:00:00 532 17 06032013 2013-06-04 08:00:00 434 18 06032013 2013-06-04 09:00:00 326 19 06032013 2013-06-04 10:00:00 310 20 06032013 2013-06-04 11:00:00 292 

Then I put this data in the counter field. For instance:

 y <- counters %>% nest(-counter) y # A tibble: 140 × 2 counter data <chr> <list> 1 06032013 <tibble [91 × 2]> 2 62295051 <tibble [310 × 2]> 3 81295014 <tibble [301 × 2]> 4 81295015 <tibble [294 × 2]> 5 81295091 <tibble [303 × 2]> 6 81295092 <tibble [306 × 2]> 7 81313062 <tibble [142 × 2]> 8 81313063 <tibble [142 × 2]> 9 82295046 <tibble [139 × 2]> 10 82295050 <tibble [141 × 2]> 

I want to make a map over each nested data frame and build the xts matrix in my nested data frame. I have tried many variations of the following code:

 y %>% mutate(stuff = map(xts(data$total, order.by = data$date_time))) 

Error in data$date_time : object of type 'closure' is not subsettable .

Any thoughts would be great!

Answer 1

@ Michael Griffiths thanks you for your help! The following code worked for me:

 y %>% mutate(stuff = map(data, ~xts(order.by = .x$date_time))) # A tibble: 140 × 3 counter data stuff <fctr> <list> <list> 1 06032013 <tibble [91 × 2]> <S3: xts> 2 62295051 <tibble [310 × 2]> <S3: xts> 3 81295014 <tibble [301 × 2]> <S3: xts> 4 81295015 <tibble [294 × 2]> <S3: xts> 5 81295091 <tibble [303 × 2]> <S3: xts> 6 81295092 <tibble [306 × 2]> <S3: xts> 7 81313062 <tibble [142 × 2]> <S3: xts> 8 81313063 <tibble [142 × 2]> <S3: xts> 9 82295046 <tibble [139 × 2]> <S3: xts> 10 82295050 <tibble [141 × 2]> <S3: xts> # ... with 130 more rows 

Still not 100% sure why. But hey, it worked.