Adding a static element across slider steps in a R plotly graph - r

Question

I am giving a tutorial on MLE and am trying to figure out how to add a static grouping of points to a plotly graph. Obviously the idea is that as I slide the normal distributions over you can see that the points correspond to a lower or higher likeihood. However, I can only get the points to appear on the first frame.
x <- seq(0, 10, length.out = 1000)
aval <- list()
for (step in 1:6) {
aval[[step]] <- list(
visible = FALSE,
name = paste0('v = ', step),
x = x,
y = dnorm(x, step+1)
)
}
aval[3][[1]]$visible = TRUE
steps <- list()
fig <- plot_ly()
for (i in 1:6) {
fig <-
add_lines(
fig,
x = aval[i][[1]]$x,
y = aval[i][[1]]$y,
visible = aval[i][[1]]$visible,
name = aval[i][[1]]$name,
type = 'scatter',
mode = 'lines',
hoverinfo = 'name',
line = list(color = '00CED1'),
showlegend = FALSE
)
step <- list(args = list('visible', rep(FALSE, length(aval))),method = 'restyle')
step$args[[2]][i] = TRUE
steps[[i]] = step
}
fig <- fig %>% add_markers(x = c(4.5,5,5.5), y = c(0,0,0))
# add slider control to plot
fig <- fig %>%
layout(sliders = list(list(
active = 0,
currentvalue = list(prefix = "Frequency: "),
steps = steps
)))
fig

Answer 1

Why don't you use plotly's animation capabilities?
But regardless of whether you define custom steps or you use the frame parameter, you'll have to provide the "static" points for each step:
library(plotly)
library(data.table)
f <- 1:6
x <- seq(0, 10, length.out = 1000)
y <- unlist(lapply(f+1, dnorm, x = x))
DT <- CJ(f, x) # like expand.grid()
DT[, y := y]
DT[, step := paste0("step-", f)]
staticDT <- CJ(f, x = c(4.5,5,5.5), y = 0)
staticDT[, step := paste0("step-", f)]
fig <- plot_ly(
data = DT,
x = ~x,
y = ~y,
frame = ~step,
type = 'scatter',
mode = 'lines',
showlegend = FALSE,
color = I('#00CED1')
)
fig <- add_trace(
fig,
data = staticDT,
x = ~x,
y = ~y,
frame = ~step,
type = 'scatter',
mode = 'markers',
showlegend = FALSE,
color = I('red'),
inherit = FALSE
)
fig <- animation_opts(
fig, transition = 0, redraw = FALSE
)
fig <- animation_slider(
fig, currentvalue = list(prefix = "Frequency: ")
)
fig