Using a loop variable to specify color in matplotlib

Question

I have many files of data and I want to plot all of them on the same plot but with different colors. I am using the following code

from pylab import loadtxt, average, std, argsort
from os import listdir
from fnmatch import fnmatch
import matplotlib.pyplot as plt


a=[]
for file in listdir('.'):
   if fnmatch(file,'A10data*'):
      a+=[str(file)]



for file in a:
  T,m_abs, m_abs_err,m_phy,m_phy_err = loadtxt(file,unpack=True)
  T_sort = argsort(T)
  plt.xlim(0.00009,10.1)
  plt.ylim(-1,350)

  plt.semilogx(T[T_sort],m_abs[T_sort],'ro-')
  plt.errorbar(T[T_sort],m_abs[T_sort],yerr=m_abs_err[T_sort],fmt='ro')
  plt.semilogx(T[T_sort],m_phy[T_sort],'r^-')
  plt.errorbar(T[T_sort],m_phy[T_sort],yerr=m_phy_err[T_sort],fmt='r^')


plt.show()

Probably I can use an integer and use the integer to specify the color of the plot. Can someone help me with the syntax?

Side note: you should check out the glob standard module.

Eric O. Lebigot
– Eric O. Lebigot

2012-07-08 15:51:35 +00:00
Commented Jul 8, 2012 at 15:51 — Eric O. Lebigot
– Eric O. Lebigot, Commented Jul 8, 2012 at 15:51

Eric O. Lebigot · Accepted Answer · 2012-07-09 00:55:11Z

2

If the number of files/plots is small, you could make an array of colors that is the same length as array called a above: something like:


colors = ["red", "blue" , "green", "orange", "purple"]
ncolor = 0
for file in a:
    plt.semilogx(T[T_sort], m_abs[T_sort], 'o-', color=colors[ncolor])
    ncolor+=1

edited Jul 9, 2012 at 0:55

Eric O. Lebigot

95.1k49 gold badges223 silver badges263 bronze badges

answered Jul 8, 2012 at 15:59

reptilicus

10.4k6 gold badges59 silver badges80 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

tacaswell Over a year ago

Slightly more pythonic you can use for file,c in zip(a,colors): and plt.semilogx(...,color=c)

Eric O. Lebigot Over a year ago

Even more robust and pythonic: 'zip(a, itertools.cycle(colors))', which automatically cycles through the colors.

Collectives™ on Stack Overflow

Using a loop variable to specify color in matplotlib

1 Answer 1

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related