IndexError happens in pythonista 3

[Kangaroo]

import matplotlib.pyplot as plt;

x = [ ];
y = [ ];

readFile = open('xy.txt','r');

for line in readFile:
# file is open with a line in variable 'line'
# do something with this line
print(line);
# split the line based on whitespace
splitUP = line.split();

print('x = ',splitUP[0],'and y = ',splitUP[1]);
# add x and y to the arrays
x.append(splitUP[0]);
y.append(splitUP[1]);

When I run it , it shows IndexError: list index out of the range

[Cethric]

Without seeing the data or the complete stack trace I can only guess what the issue is. But two possibilities come to mind:

1. line is a white space character so there is nothing to split which results in 2).
2. splitUP has a value of ['xy'] instead of ['x', 'y']
   Either way try printing the value of splitUP Without breaking it first. IE print(splitUP) and see what that gives.

[Kangaroo]

This is my data

2 1.69
3 3.25
4 2.44
5 3.45
6 6.29
7 3.94
8 5.23
9 5.78
10 6.31
11 8.25
12 7.84

Stake:

---------------------------below is my program----------------------------

import matplotlib.pyplot as plt;

x = [ ];
y = [ ];

readFile = open('xy.txt','r');

for line in readFile:

print(line);

splitUP = line.split();

print('x =',splitUP[0],'and y =',splitUP[1]);

x.append(splitUP[0]);
y.append(splitUP[1]);

readFile.close();

plt.plot(x,y);

plt.show();

[Kangaroo]

Stake:

print('x =',splitUP[0],'and y =',splitUP[1]);
IndexError: list index out of range

[JonB]

you should use try, then catch the IndexError and print both the line, and the split. You may find that you have a blank line at the end of your file, etc.

[JonB]

by the way, you might find numpy.loadtxt the best way to read this type of file, especially if you are using this in matplotlub or numpy.

[ccc]

I would add the line print(splitUP, len(splitUP)) before your current print() line and I would remove all those unnecessary semicolons ;-). I think the others are correct. You have a blank line in your input.

[Kangaroo]

Thank you guys! I do have a blank line in my file but now it's gone!