I took me a long time to understand how to use a loop into a plotly plot. The trick is to use the evaluate=TRUE option. Watch out! I don’t know why but apparently, you need to re-make the layout at each loop. Don’t forget that most of the time you can use the option color = my_groups to draw several traces. (See graph #121). Does’nt work anymore with the new version of plotly… Sorry for the inconvenienve. Please tell me if you have a solution…

# plotly library
library(plotly)

# Create data
my_y=rnorm(10)*3
my_x=seq(0,9)

# Let's do a first plot
p<-plot_ly(y=my_y, x=my_x , type="scatter", mode="markers+lines")

# Add 5 trace to this graphic with a loop!
for(i in 1:3){
    my_y=rnorm(10)
    p<-add_trace(p, y=~my_y, x=~my_x , type="scatter", mode="markers+lines" )
    #p=layout(yaxis=list(range=c(-10,9)))
}

p