This transition allows you to transition between a range of filtering conditions. The conditions are expressed as logical statements and rows in the data will be retained if the statement evaluates to TRUE. It is possible to keep filtered data on display by setting keep = TRUE which will let data be retained as the result of the exit function. Note that if data is kept the enter function will have no effect.

transition_filter(transition_length = 1, filter_length = 1, ...,
wrap = TRUE, keep = FALSE)

## Arguments

transition_length The relative length of the transition. Will be recycled to match the number of states in the data The relative length of the pause at the states. Will be recycled to match the number of states in the data A number of expressions to be evaluated in the context of the layer data, returning a logical vector. If the expressions are named, the name will be available as a frame variable. Should the animation wrap-around? If TRUE the last filter will be transitioned into the first. Should rows that evaluates to FALSE be kept in the data as it looks after exit has been applied

## Label variables

transition_filter makes the following variables available for string literal interpretation, in addition to the general ones provided by animate():

• transitioning is a boolean indicating whether the frame is part of the transitioning phase

• previous_filter The name of the last filter the animation was at

• closest_filter The name of the filter closest to this frame

• next_filter The name of the next filter the animation will be part of

• previous_expression The expression of the last filter the animation was at

• closest_expression The expression of the filter closest to this frame

• next_expression The expression of the next filter the animation will be part of

## Object permanence

transition_filter does not link rows across data to the same graphic element, so elements will be defined uniquely by each row. If keep = TRUE the rows not matching the conditions of a filter is not removed from the plot after the exit animation, and a possible subsequent enter will begin from the state they were left in, rather than enter anew from the state defined by the enter function.

## Computed Variables

It is possible to use variables calculated by the statistic to define the transition. Simply inclose the variable in stat() in the same way as when using computed variables in aesthetics.

Other transitions: transition_components, transition_events, transition_layers, transition_manual, transition_null, transition_reveal, transition_states, transition_time

## Examples

anim <- ggplot(iris, aes(Petal.Width, Petal.Length, colour = Species)) +
geom_point() +
transition_filter(
transition_length = 2,
filter_length = 1,
Setosa = Species == 'setosa',
Long = Petal.Length > 4,
Wide = Petal.Width > 2
) +
ggtitle(
'Filter: {closest_filter}',
subtitle = '{closest_expression}'
) +
exit_fly(y_loc = 0)

# Setting keep = TRUE allows you to keep the culled data on display. Only
# exit functions will be used in that case (as elements enters from the
# result of the exit function)
anim2 <- ggplot(iris, aes(Petal.Width, Petal.Length, colour = Species)) +
geom_point() +
transition_filter(
transition_length = 2,
filter_length = 1,
Setosa = Species == 'setosa',
Long = Petal.Length > 4,
Wide = Petal.Width > 2,
keep = TRUE
) +
ggtitle(
'Filter: {closest_filter}',
subtitle = '{closest_expression}'
) +
exit_recolour(colour = 'grey') +
exit_shrink(size = 0.5)