R: Stack overlapping data.

compute_stack {ggvis} | R Documentation

## Stack overlapping data.

### Description

Stack overlapping data.

### Usage

    compute_stack(x, stack_var = NULL, group_var = NULL)

### Arguments

`x` | A data object
`stack_var` | A string specifying the stacking variable.
`group_var` | A string specifying the grouping variable.

### Value

A data frame with columns:

`stack_upr_` | the lower y coordinate for a stack bar
`stack_lwr_` | the upper y coordinate for a stack bar

### Examples

    mtcars %>% cbind(count = 1) %>% compute_stack(~count, ~cyl)

    # Shouldn't use or affect existing grouping
    mtcars %>% cbind(count = 1) %>% group_by(am) %>% compute_stack(~count, ~cyl)

    # If given a ggvis object, will use x variable for stacking by default
    mtcars %>% ggvis(x = ~cyl, y = ~wt) %>%
      compute_stack(stack_var = ~wt, group_var = ~cyl) %>%
      layer_rects(x = ~cyl - 0.5, x2 = ~cyl + 0.5, y = ~stack_upr_,
        y2 = ~stack_lwr_)

    # Collapse across hair & eye colour data across sex
    hec <- as.data.frame(xtabs(Freq ~ Hair + Eye, HairEyeColor))
    hec %>% compute_stack(~Freq, ~Hair)

    # Without stacking - bars overlap
    hec %>% ggvis(~Hair, ~Freq, fill = ~Eye, fillOpacity := 0.5) %>%
      layer_rects(y2 = 0, width = band())

    # With stacking
    hec %>% ggvis(x = ~Hair, y = ~Freq, fill = ~Eye, fillOpacity := 0.5) %>%
      compute_stack(~Freq, ~Hair) %>%
      layer_rects(y = ~stack_lwr_, y2 = ~stack_upr_, width = band())

    # layer_bars stacks automatically:
    hec %>% ggvis(~Hair, ~Freq, fill = ~Eye, fillOpacity := 0.5) %>%
      group_by(Eye) %>%
      layer_bars(width = 1)

[Package ggvis version 0.4.3 Index]