Random walk

1D

##################################################
N = 10000  
signal = vector(length = N)  
signal[1] = 0 
for (i in 2:N)  
{  
  # random select one offset (from [-1,1]) to signal[i-1]  
  signal[i] = signal[i-1] + sample(c(-1,1),1)   
}  
plot( signal,type = 'l',col = 'yellow')

2D

##################################################
N = 100
x = vector(length = N)
y = vector(length = N)
x[1] = 0
y[1] = 0
for (i in 2:N)
{
  x[i] = x[i-1] + rnorm(1)
  y[i] = y[i-1] + rnorm(1)
}

plot(x,y,type = 'l', col='red')

3D

##################################################
#source("http://bioconductor.org/biocLite.R")
#biocLite("scatterplot3d")
library("scatterplot3d")
N = 100
x = vector(length = N)
y = vector(length = N)
z = vector(length = N)
x[1] = 0
y[1] = 0
z[1] = 0
for (i in 2:N)
{
  x[i] = x[i-1] + rnorm(1)
  y[i] = y[i-1] + rnorm(1)
  z[i] = z[i-1] + rnorm(1)
}
scatterplot3d(x, y, z,color="red", col.axis="blue", type="h", col.grid="lightblue",main="scatterplot3d - 1", pch=20)

scatterplot3d(x, y, z,color="red", col.axis="blue", type="l", col.grid="lightblue",main="scatterplot3d - 1", pch=20)

Session information

sessionInfo()

R version 3.4.2 (2017-09-28)
Platform: x86_64-apple-darwin15.6.0 (64-bit)
Running under: macOS Sierra 10.12.1

Matrix products: default
BLAS: /Library/Frameworks/R.framework/Versions/3.4/Resources/lib/libRblas.0.dylib
LAPACK: /Library/Frameworks/R.framework/Versions/3.4/Resources/lib/libRlapack.dylib

locale:
[1] zh_CN.UTF-8/zh_CN.UTF-8/zh_CN.UTF-8/C/zh_CN.UTF-8/zh_CN.UTF-8

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

other attached packages:
[1] scatterplot3d_0.3-40

loaded via a namespace (and not attached):
 [1] compiler_3.4.2  backports_1.1.2 magrittr_1.5    rprojroot_1.3-2
 [5] tools_3.4.2     htmltools_0.3.6 yaml_2.1.16     Rcpp_0.12.14   
 [9] stringi_1.1.6   rmarkdown_1.8   knitr_1.18      git2r_0.21.0   
[13] stringr_1.2.0   digest_0.6.14   evaluate_0.10.1