import sys
from numpy import loadtxt              # pandas read.csv seems to the most elegant method, but this is a simple ascii file reader
import matplotlib.pyplot as plt

 

if (len(sys.argv) > 1):
    infile = sys.argv[1]
    x,y = loadtxt(infile,unpack=True,usecols=(0,1))
    fig = plt.figure()
    ax = fig.add_subplot(111)
    ax.plot(x,y)
    # could stop here, but can pretty it up a little

    xspan = max(x) -min(x)
    yspan = max(y) -min(y)
    minx = min(x) - 0.05*xspan
    maxx = max(x) + 0.05*xspan
    miny = min(y) - 0.05*yspan
    maxy = max(y) + 0.05*yspan
    ax.axis([minx,maxx,miny,maxy])
    if (len(sys.argv) > 2) :
        ax.set_title(sys.argv[2])
    plt.show()

else:
    print("Syntax: xyploter <infile> [title]")