Random Walk in ggplot2

How to make Random Walk in ggplot2 with Plotly.

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Plotly is a free and open-source graphing library for R. We recommend you read our Getting Started guide for the latest installation or upgrade instructions, then move on to our Plotly Fundamentals tutorials or dive straight in to some Basic Charts tutorials.

A random walk can be thought of as a random process in which a token or a marker is randomly moved around some space, that is, a space with a metric used to compute distance. In the visualizations below, we will be using scatter plots as well as a colorscale to denote the time sequence of the walk.

Random Walk in 1D

The jitter in the data points along the x and y axes are meant to illuminate where the points are being drawn and what the tendency of the random walk is.

library(plotly)
library(ggplot2)

P1 <- cumsum(rnorm(1000))
dat <- data.frame(x = seq_along(P1), y = P1)
p <- ggplot(dat, aes(x = x, y = y)) + geom_line()

ggplotly(p)

Random Walk in 2D

library(plotly)
require(ggplot2)

random_walk <- function(n.org, steps, left.p = .5, up.p = .5, plot = TRUE){


whereto <- matrix(ncol = 2)

for(x in 1:n.org){
walker <- matrix(c(0,0), nrow = steps+1, ncol = 2, byrow = T)

for(i in 1:steps){
# left/right = 1/0
horizontal <- rbinom(1, 1, left.p)

# distance 2
h.dist <- abs(rnorm(1, 0, 1))

# Horizontal Movement
if(horizontal == 0){
walker[i+1,1] <- walker[i,1] + h.dist
}
if(horizontal == 1){
walker[i+1,1] <- walker[i,1] - h.dist
}

# up/down = 1/0
vertical <- rbinom(1, 1, up.p)

#distance 2
v.dist <- abs(rnorm(1, 0, 1))

# Vertical Movement
if(vertical == 1){
walker[i+1,2] <- walker[i,2] + v.dist
}
if(vertical == 0){
walker[i+1,2] <- walker[i,2] - v.dist
}
}

whereto <- rbind(whereto, walker)
}

id <- rep(1:n.org, each = 1001)
colnames(whereto) <- c("x" , "y")
whereto <- as.data.frame(whereto)
whereto <- cbind(whereto[2:nrow(whereto),], org = factor(id))

p <- ggplot(whereto, aes(x = x, y = y, colour = org))
p <- p + geom_path()

return(p)
}

p <- random_walk(1, 1000, .5, .5)

ggplotly(p)

What About Dash?

Dash for R is an open-source framework for building analytical applications, with no Javascript required, and it is tightly integrated with the Plotly graphing library.

Learn about how to install Dash for R at https://dashr.plot.ly/installation.

Everywhere in this page that you see fig, you can display the same figure in a Dash for R application by passing it to the figure argument of the Graph component from the built-in dashCoreComponents package like this:

library(plotly)

fig <- plot_ly() 
# fig <- fig %>% add_trace( ... )
# fig <- fig %>% layout( ... ) 

library(dash)
library(dashCoreComponents)
library(dashHtmlComponents)

app <- Dash$new()
app$layout(
    htmlDiv(
        list(
            dccGraph(figure=fig) 
        )
     )
)

app$run_server(debug=TRUE, dev_tools_hot_reload=FALSE)