R: Count data at each location of a categorical variable

compute_tabulate {ggvis} | R Documentation

## Count data at each location of a categorical variable

### Description

Count data at each location of a categorical variable

### Usage

    compute_tabulate(x, x_var, w_var = NULL)

### Arguments

`x` | Dataset-like object to count. Built-in methods for data frames, grouped data frames and ggvis visualisations.
`x_var, w_var` | Names of x and weight variables.

### Value

A data frame with columns:

`count_` | the number of points
`x_` | value of bin

### See Also

`compute_bin` For counting cases within ranges of a continuous variable.

`compute_count` For counting cases at specific locations of a continuous variable. This is useful when the variable is continuous but the data is granular.

### Examples

    library(dplyr)
    # The tabulated column must be countable (not numeric)
    ## Not run: mtcars %>% compute_tabulate(~cyl)
    mtcars %>% mutate(cyl = factor(cyl)) %>% compute_tabulate(~cyl)

    # Or equivalently:
    mtcars %>% compute_tabulate(~factor(cyl))

    # If there's one weight value at each x, it effectively just renames columns.
    pressure %>% compute_tabulate(~factor(temperature), ~pressure)

    # It doesn't matter whether you transform inside or outside of a vis
    mtcars %>% compute_tabulate(~factor(cyl)) %>%
      ggvis(x = ~x_, y = ~count_, y2 = 0) %>%
      layer_rects(width = band())

    mtcars %>%
      ggvis(x = ~x_, y = ~count_, y2 = 0) %>%
      compute_tabulate(~factor(cyl)) %>%
      layer_rects(width = band())

    # compute_tabulate is used automatically in layer_bars when no y prop
    # is supplied.
    mtcars %>% ggvis(x = ~factor(cyl)) %>% layer_bars()

[Package ggvis version 0.4.3 Index]