tally() and count()

tally_count.R

``` r
library(dplyr)

x <- tibble(a=c(1, 2, 2, 3)) 

x %>% group_by(a) %>% summarise(n())
#> # A tibble: 3 x 2
#>       a `n()`
#>   <dbl> <int>
#> 1     1     1
#> 2     2     2
#> 3     3     1

x %>% group_by(a) %>% tally()
#> # A tibble: 3 x 2
#>       a     n
#>   <dbl> <int>
#> 1     1     1
#> 2     2     2
#> 3     3     1

x %>% count(a)
#> # A tibble: 3 x 2
#>       a     n
#>   <dbl> <int>
#> 1     1     1
#> 2     2     2
#> 3     3     1

x %>% group_by(a) %>% add_tally()
#> # A tibble: 4 x 2
#> # Groups:   a [3]
#>       a     n
#>   <dbl> <int>
#> 1     1     1
#> 2     2     2
#> 3     2     2
#> 4     3     1

x %>% add_count(a)
#> # A tibble: 4 x 2
#>       a     n
#>   <dbl> <int>
#> 1     1     1
#> 2     2     2
#> 3     2     2
#> 4     3     1



x %>% group_by(a) %>% tally(a)
#> # A tibble: 3 x 2
#>       a     n
#>   <dbl> <dbl>
#> 1     1     1
#> 2     2     4
#> 3     3     3

x %>% group_by(a) %>% add_tally(a)
#> # A tibble: 4 x 2
#> # Groups:   a [3]
#>       a     n
#>   <dbl> <dbl>
#> 1     1     1
#> 2     2     4
#> 3     2     4
#> 4     3     3



x %>% count()
#> # A tibble: 1 x 1
#>       n
#>   <int>
#> 1     4

x %>% add_count()
#> # A tibble: 4 x 2
#>       a     n
#>   <dbl> <int>
#> 1     1     4
#> 2     2     4
#> 3     2     4
#> 4     3     4
```

Created on 2018-07-24 by the [reprex package](http://reprex.tidyverse.org) (v0.2.0).