Setting different color for each series in scatter plot on matplotlib

Question

Suppose I have three data sets   X    1 2 3 4  Y1    4 8 12 16  Y2    1 4 9 16    I can scatter plot this   from matplotlib import pyplot as plt plt scatter X Y1 color  red   plt scatter X Y2 color  blue   plt show     How can I do this with 10 sets    I searched for this and could find any reference to what I m asking   Edit  clarifying  hopefully  my question    If I call scatter multiple times  I can only set the same color on each scatter  Also  I know I can set a color array manually but I m sure there is a better way to do this   My question is then   How can I automatically scatter-plot my several data sets  each with a different color    If that helps  I can easily assign a unique number to each data set

User · Answer

The normal way to plot plots with points in different colors in matplotlib is to pass a list of colors as a parameter.

E.g.:

import matplotlib.pyplot
matplotlib.pyplot.scatter([1,2,3],[4,5,6],color=['red','green','blue'])

When you have a list of lists and you want them colored per list. I think the most elegant way is that suggesyted by @DSM, just do a loop making multiple calls to scatter.

But if for some reason you wanted to do it with just one call, you can make a big list of colors, with a list comprehension and a bit of flooring division:

import matplotlib
import numpy as np

X = [1,2,3,4]
Ys = np.array([[4,8,12,16],
      [1,4,9,16],
      [17, 10, 13, 18],
      [9, 10, 18, 11],
      [4, 15, 17, 6],
      [7, 10, 8, 7],
      [9, 0, 10, 11],
      [14, 1, 15, 5],
      [8, 15, 9, 14],
       [20, 7, 1, 5]])
nCols = len(X)  
nRows = Ys.shape[0]

colors = matplotlib.cm.rainbow(np.linspace(0, 1, len(Ys)))

cs = [colors[i//len(X)] for i in range(len(Ys)*len(X))] #could be done with numpy's repmat
Xs=X*nRows #use list multiplication for repetition
matplotlib.pyplot.scatter(Xs,Ys.flatten(),color=cs)

cs = [array([ 0.5,  0. ,  1. ,  1. ]),
 array([ 0.5,  0. ,  1. ,  1. ]),
 array([ 0.5,  0. ,  1. ,  1. ]),
 array([ 0.5,  0. ,  1. ,  1. ]),
 array([ 0.28039216,  0.33815827,  0.98516223,  1.        ]),
 array([ 0.28039216,  0.33815827,  0.98516223,  1.        ]),
 array([ 0.28039216,  0.33815827,  0.98516223,  1.        ]),
 array([ 0.28039216,  0.33815827,  0.98516223,  1.        ]),
 ...
 array([  1.00000000e+00,   1.22464680e-16,   6.12323400e-17,
          1.00000000e+00]),
 array([  1.00000000e+00,   1.22464680e-16,   6.12323400e-17,
          1.00000000e+00]),
 array([  1.00000000e+00,   1.22464680e-16,   6.12323400e-17,
          1.00000000e+00]),
 array([  1.00000000e+00,   1.22464680e-16,   6.12323400e-17,
          1.00000000e+00])]

User · Answer

A MUCH faster solution for large dataset and limited number of colors is the use of Pandas and the groupby function   import pandas as pd import numpy as np import matplotlib pyplot as plt import time     a generic set of data with associated colors nsamples 1000 x np random uniform 0 10 nsamples  y np random uniform 0 10 nsamples  colors  0  r  1  g  2  b  3  k   c  colors i  for i in np round np random uniform 0 3 nsamples  0    plt close  all       Fast  Scatter plotting starttime time time     1  make a dataframe df pd DataFrame   df  x   x df  y   y df  c   c plt figure     2  group the dataframe by color and loop for g b in df groupby by  c        plt scatter b  x   b  y   color g  print  Fast execution time    time time  -starttime      Slow  Scatter plotting starttime time time   plt figure     2  group the dataframe by color and loop for i in range len x        plt scatter x i  y i  color c i   print  Slow execution time    time time  -starttime   plt show

User · Answer

This works for me   for each series  use a random rgb colour generator  c   color np random random sample    np random random sample    np random random sample

User · Answer

This question is a bit tricky before Jan 2013 and matplotlib 1 3 1  Aug 2013   which is the oldest stable version you can find on matpplotlib website  But after that it is quite trivial   Because present version of matplotlib pylab scatter support assigning  array of colour name string  array of float number with colour map  array of RGB or RGBA   this answer is dedicate to  Oxinabox s endless passion for correcting the 2013 version of myself in 2015     you have two option of using scatter command with multiple colour in a single call    as pylab scatter command support use RGBA array to do whatever colour you want  back in early 2013  there is no way to do so  since the command only support single colour for the whole scatter point collection  When I was doing my 10000-line project I figure out a general solution to bypass it  so it is very tacky  but I can do it in whatever shape  colour  size and transparent  this trick also could be apply to draw path collection  line collection       the code is also inspired by the source code of pyplot scatter  I just duplicated what scatter does without trigger it to draw    the command pyplot scatter return a PatchCollection Object  in the file  matplotlib collections py  a private variable  facecolors in Collection class and a method set facecolors    so whenever you have a scatter points to draw you can do this     rgbaArr is a N 4 array of float numbers you know what I mean   X is a N 2 array of coordinates   axx is the axes object that current draw  you get it from   axx   fig gca      also import these  to recreate the within env of scatter command  import matplotlib markers as mmarkers import matplotlib transforms as mtransforms from matplotlib collections import PatchCollection import matplotlib markers as mmarkers import matplotlib patches as mpatches     define this function   m is a string of scatter marker  it could be  o    s  etc     s is the size of the point  use 1 0   dpi  get it from axx figure dpi def addPatch point m  s  dpi       marker obj   mmarkers MarkerStyle m      path   marker obj get path       trans   mtransforms Affine2D   scale np sqrt s 5  dpi 72 0      ptch   mpatches PathPatch path  fill   True  transform   trans      return ptch  patches        markerArr is an array of maker string    o    s    o        sizeArr is an array of size float   1 0  1 0  0 5      for m  s in zip markerArr  sizeArr       patches append addPatch point m  s  axx figure dpi    pclt   PatchCollection                  patches                  offsets   zip X   0   X   1                    transOffset   axx transData   pclt set transform mtransforms IdentityTransform    pclt set edgecolors  none     it s up to you pclt  facecolors   rgbaArr    in the end  when you decide to draw axx add collection pclt    and call axx s parent to draw idle

User · Answer

An easy fix  If you have only one type of collections  e g  scatter with no error bars  you can also change the colours after that you have plotted them  this sometimes is easier to perform   import matplotlib pyplot as plt from random import randint import numpy as np   Let s generate some random X  Y data X      frst group   second group       X      randint 0 50  for i in range 0 5   for i in range 0 24   Y      randint 0 50  for i in range 0 5   for i in range 0 24   labels   range 1 len X  1   fig   plt figure   ax   fig add subplot 111  for x y lab in zip X Y labels           ax scatter x y label lab    The only piece of code that you need    Now this is actually the code that you need  an easy fix your colors just cut and paste not you need ax  colormap   plt cm gist ncar  nipy spectral  Set1 Paired   colorst    colormap i  for i in np linspace 0  0 9 len ax collections           for t j1 in enumerate ax collections       j1 set color colorst t     ax legend fontsize  small     The output gives you differnent colors even when you have many different scatter plots in the same subplot

User · Answer

I don t know what you mean by  manually    You can choose a colourmap and make a colour array easily enough  import numpy as np import matplotlib pyplot as plt import matplotlib cm as cm  x   np arange 10  ys    i x  i x   2 for i in range 10    colors   cm rainbow np linspace 0  1  len ys    for y  c in zip ys  colors       plt scatter x  y  color c    Or you can make your own colour cycler using itertools cycle and specifying the colours you want to loop over  using next to get the one you want   For example  with 3 colours  import itertools  colors   itertools cycle   quot r quot    quot b quot    quot g quot    for y in ys      plt scatter x  y  color next colors     Come to think of it  maybe it s cleaner not to use zip with the first one neither  colors   iter cm rainbow np linspace 0  1  len ys     for y in ys      plt scatter x  y  color next colors

User · Answer

You can always use the plot   function like so   import matplotlib pyplot as plt  import numpy as np  x   np arange 10  ys    i x  i x   2 for i in range 10   plt figure   for y in ys      plt plot x  y   o   plt show

[python] Setting different color for each series in scatter plot on matplotlib

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