nest function doesn't seem to be right?

[happyshows]

chickwts %>% tbl_df
Source: local data frame [71 x 2]

Hi,

I was running the code in documentation and it seems the nested data is off by one row.

weight feed
(dbl) (fctr)
1 179 horsebean
2 160 horsebean
3 136 horsebean
4 227 horsebean
5 217 horsebean
6 168 horsebean
7 108 horsebean
8 124 horsebean
9 143 horsebean
10 140 horsebean
.. ... ...

chickwts %>% nest(weight)
feed data
1 horsebean 368, 390, 379, 260, 404, 318, 352, 359, 216, 222, 283, 332
2 linseed 179, 160, 136, 227, 217, 168, 108, 124, 143, 140
3 soybean 309, 229, 181, 141, 260, 203, 148, 169, 213, 257, 244, 271
4 sunflower 325, 257, 303, 315, 380, 153, 263, 242, 206, 344, 258
5 meatmeal 243, 230, 248, 327, 329, 250, 193, 271, 316, 267, 199, 171, 158, 248
6 casein 423, 340, 392, 339, 341, 226, 320, 295, 334, 322, 297, 318

[happyshows]

sessionInfo()
[1] dplyr_0.4.3.9000 tidyr_0.4.0.9000

[ginolhac]

I agree that the nesting seems not be right. Following the blog post

  dplyr::filter(continent == "Asia", country == "Afghanistan")
Source: local data frame [12 x 6]

       country continent  year lifeExp      pop gdpPercap
        (fctr)    (fctr) (int)   (dbl)    (int)     (dbl)
1  Afghanistan      Asia  1952  28.801  8425333  779.4453
2  Afghanistan      Asia  1957  30.332  9240934  820.8530
3  Afghanistan      Asia  1962  31.997 10267083  853.1007
4  Afghanistan      Asia  1967  34.020 11537966  836.1971

While, nest() gives other values

by_country <- gapminder::gapminder %>% 
    group_by(continent, country) %>% 
    nest()
by_country[1, ] # check Asia + Afghanistan
Source: local data frame [1 x 3]

  continent     country            data
     (fctr)      (fctr)           (chr)
1      Asia Afghanistan <tbl_df [12,4]>
# unnest for this row
by_country[1,]$data[[1]]
Source: local data frame [12 x 4]

    year lifeExp      pop gdpPercap
   (int)   (dbl)    (int)     (dbl)
1   1952  43.077  9279525  2449.008
2   1957  45.685 10270856  3013.976
3   1962  48.303 11000948  2550.817
4   1967  51.407 12760499  3246.992

Actually, data come from Africa, Algeria seems like the data are arranged per continent, while grouped columns are arranged by country.

tidyr 0.4.0
dplyr 0.4.3

[hadley]

Could you please provide a minimal reproducible example that I can easily copy and paste into R?

[happyshows]

works now, thanks.

[ginolhac]

perfect, thanks a lot