Matplotlib giving some errors while ploting a graph from file

Question

So, here I'm trying to plot a graph using the coordinates that are provided in a file. I'm opening the file and setting the coordinates in an array to feed the array as in put to the graph.

Code:

import matplotlib
import matplotlib.pyplot as plt

x=[]
y=[]

readFile=open("coordinates.txt","r")
data = readFile.read().split("\n")

print(data)

for i in data:
    val = i.split(",")
    x.append(int(val[0]))
    y.append(int(val[1]))

plt.plot(x,y)
plt.show()

Output:

['3,22', '5,16', '-2,8', '10,43', '4,0', '']
Traceback (most recent call last):
  File "/home/nishantsikri/matplotlib from file.py", line 14, in <module>
    x.append(int(val[0]))
ValueError: invalid literal for int() with base 10: ''

ImportanceOfBeingErnest · Accepted Answer · 2018-02-15 19:26:25Z

1

The problem is that you have an empty line at the end of your file. One would need to check for that an not append it to the lists.

However, it seems the complete code can be condensed to

import numpy as np
import matplotlib.pyplot as plt

x,y = np.genfromtxt("coordinates.txt", unpack=True, delimiter=",")
plt.plot(x,y)
plt.show()

This would also automatically take care of the empty line.

edited Feb 15, 2018 at 19:26

answered Feb 15, 2018 at 18:39

ImportanceOfBeingErnest

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Comments

Equinox · Accepted Answer · 2018-02-15 18:46:05Z

0

You have trailing spaces in your file. Use strip to remove trailing spaces.

data = readFile.read().strip().split("\n")

answered Feb 15, 2018 at 18:46

Equinox

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