Plot multiple lines data series each with unique color in R

Question

I am fairly new to R and I have the following queries    I am trying to generate a plot in R which has multiple lines  data series   Each of these lines is a category and I want it to have a unique color    Currently my code is setup in this way    First  I am creating an empty plot    plot 1 type  n  xlim c 1 10  ylim c 0 max y  xlab  ID   ylab  Frequency     Then for each of my category  I am plotting lines in this empty plot using a  for  loop like so    for  category in categories   lines data frame for this category  type  o   col sample rainbow 10    lwd 2      There are 8 categories here  and so there are 8 lines produced in the plot  As you can see  I am trying to sample a color from the rainbows   function to generate a color for each line    However  when the plot is generated  I find that there are multiple lines which have the same color  For instance  3 of those 8 lines have green color    How do I make each of these 8 lines have a unique color     Also  how do I reflect this uniqueness in the legend of the plot   I was trying to lookup the legend   function  however it was not clear which parameter I should use to reflect this unique color for each category     Any help or suggestions would be much appreciated

User · Answer

In addition to  joran s answer using the base plot function with a for loop  you can also use base plot with lapply   plot 0 0 xlim   c -10 10  ylim   c -10 10  type    n    cl  lt - rainbow 5   invisible lapply 1 5  function i  lines -10 10 runif 21 -10 10  col   cl i  type    b        Here  the invisible function simply serves to prevent lapply from producing a list output in your console  since all we want is the recursion provided by the function  not a list       As you can see  it produces the exact same result as using the for loop approach   So why use lapply   Though lapply has been shown to perform faster better than for in R  e g   see here  though see here for an instance where it s not   in this case it performs roughly about the same   Upping the number of lines to 50000 for both the lapply and for approaches took my system 46 3 and 46 55 seconds  respectively    So  although lapply was just slightly faster  it was negligibly so  This speed difference might come in handy with larger more complex graphing  but let s be honest  50000 lines is probably a pretty good ceiling       So the answer to  why lapply    it s simply an alternative approach that works equally as well

User · Answer

Here is another way to add lines using plot     First  use function par new T   option    http   cran r-project org doc contrib Lemon-kickstart kr addat html  To color them differently you will need col     To avoid superfluous axes descriptions use xaxt  n  and yaxt  n    for second and further plots

User · Answer

If you would like a ggplot2 solution  you can do this if you can shape your data to this format  see example below     dummy data set seed 45  df  lt - data frame x rep 1 5  9   val sample 1 100  45                       variable rep paste0  category   1 9   each 5     plot ggplot data   df  aes x x  y val     geom line aes colour variable

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If your data is in wide format matplot is made for this and often forgotten about    dat  lt - matrix runif 40 1 20  ncol 4    make data  matplot dat  type   c  b   pch 1 col   1 4   plot  legend  topleft   legend   1 4  col 1 4  pch 1    optional legend   There is also the added bonus for those unfamiliar with things like ggplot that most of the plotting paramters such as pch etc  are the same using matplot   as plot

User · Answer

In case the x-axis is a factor   discrete variable  and one would like to keep the order of the variable  different values corresponding to different groups  to visualise the group effect  The following code wold do   library ggplot2  set seed 45     dummy data df  lt - data frame x rep letters 1 5   9   val sample 1 100  45                       variable rep paste0  category   1 9   each 5      This ensures that x-axis  which is a factor variable   will be ordered appropriately df x  lt - ordered df x  levels letters 1 5    ggplot data   df  aes x x  y val  group variable  color variable     geom line     geom point     ggtitle  Multiple lines with unique color      Also note that  adding group variable remove the warning information   geom path  Each group consists of only one observation  Do you need to adjust the group aesthetic

User · Answer

You have the right general strategy for doing this using base graphics  but as was pointed out you re essentially telling R to pick a random color from a set of 10 for each line  Given that  it s not surprising that you will occasionally get two lines with the same color  Here s an example using base graphics   plot 0 0 xlim   c -10 10  ylim   c -10 10  type    n    cl  lt - rainbow 5   for  i in 1 5       lines -10 10 runif 21 -10 10  col   cl i  type    b         Note the use of type    n  to suppress all plotting in the original call to set up the window  and the indexing of cl inside the for loop

User · Answer

I know  its old a post to answer but like I came across searching for the same post  someone else might turn here as well      By adding   colour in ggplot function   I could achieve the lines with different colors related to the group present in the plot      ggplot data Set6  aes x Semana  y Net Sales in pesos  group   Agencia ID  colour   as factor Agencia ID          and  geom line

User · Answer

More than one line can be drawn on the same chart by using the lines  function    Create the data for the chart  v  lt - c 7 12 28 3 41  t  lt - c 14 7 6 19 3     Give the chart file a name  png file    line chart 2 lines jpg      Plot the bar chart  plot v type    o  col    red   xlab    Month   ylab    Rain fall       main    Rain fall chart    lines t  type    o   col    blue      Save the file  dev off     OUTPUT

User · Answer

Using  Arun dummy data    here a lattice solution    xyplot val x type c  l   p   groups  variable data df auto key T

User · Answer

Here is a sample code that includes a legend if that is of interest     First create an empty plot  plot 1  type    n   xlim   c xminp  xmaxp   ylim   c 0  1         xlab    log transformed coverage   ylab    frequency      Create a list of 22 colors to use for the lines  cl  lt - rainbow 22     Now fill plot with the log transformed coverage data from the   files one by one  for i in 1 length data         lines density log data  i   coverage    col   cl i       plotcol i   lt - cl i    legend  topright   legend   c list files     col   plotcol  lwd   1         cex   0 5

[r] Plot multiple lines (data series) each with unique color in R

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