Question

I have some troubles with plotting the figure. I have a file with some results computed by application I wrote in c++ and I would like to plot the figure for the computed data.

The problem is that I don’t know the ‘max’ and ‘min’ limit on axis X and axis Y …

I tried:

# -*- coding: utf-8 -*-
#!/usr/bin/env python

import matplotlib
matplotlib.use("Agg")
import matplotlib.pyplot as plt

def plot_it(ox, oy, x_label, y_label, filename) :

    fig = plt.figure()
    axis = fig.add_subplot(111)
    plt.xlabel(x_label)
    plt.ylabel(y_label)
    plt.ylim(min(oy),max(oy))
    plt.xlim(min(ox),max(ox))
    axis.plot(ox, oy, color = 'red')
    plt.savefig(filename)
    plt.clf()
    plt.close()

filename = input("Filename (file with data)\n>")
res = []
try :
    with open(filename, 'r') as file :
        for line in file :
            line = line.rstrip('\n')
            res.append(line.split(" "))
except IOError :
    print("IO error")

if len(res) != 0 :

    ox = []
    oy = []

    x_label = str(input("OX label\n>"))
    y_label = str(input("OY label\n>"))

    for i in range(0,len(res)) :
        ox.append(res[i][0])
        oy.append(res[i][1])

    plot_it(ox, oy, x_label, y_label, 'fig_' + str(filename[:len(filename)-4]) + '.png')

Where my file is here: http://pastie.org/private/4rl64ule9ymljmp6g5bfzg (just copy it and save as file.txt)

I got those errors:

Traceback (most recent call last): File “E:/plotter.py”, line 43, in

plot_it(ox, oy, x_label, y_label, ‘fig_’ + str(filename[:len(filename)-4]) + ‘.png’) File “E:/plotter.py”, line
14, in plot_it
plt.ylim(min(oy),max(oy)) File “C:\Python27\lib\site-packages\matplotlib\pyplot.py”, line 1252, in
ylim
ret = ax.set_ylim(*args, **kwargs) File “C:\Python27\lib\site-packages\matplotlib\axes.py”, line 2642, in
set_ylim
bottom, top = mtransforms.nonsingular(bottom, top, increasing=False) File
“C:\Python27\lib\site-packages\matplotlib\transforms.py”, line 2282,
in nonsingular
if (not np.isfinite(vmin)) or (not np.isfinite(vmax)): NotImplementedError: Not implemented for this type

Answer 1

Add:

plt.ylim(min(oy),max(oy))
plt.xlim(min(ox),max(ox))

to the second block of code you give, this will set your x and limits to the min/max of your data.