How to plot data from a file?
Is it possible to plot data imported from an ASCII file.
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2 Answers
Suppose that you have a file '/tmp/DataFile' containing the following text
3;2
2;1
1;0.1
0.01;-0.9
Then you can load the two data columns into two arrays xArr and yArr by the following code
f = open('/home/tobi/tmp/DataFile', 'r')
xArr=[]
yArr=[]
line=f.readline()
while(line !=''):
xy=line.split(';')
xArr.append(float(xy[0]))
yArr.append(float(xy[1]))
line=f.readline()
Now you can do whatever you want with these array, for example plot them
list_plot(zip(xArr,yArr))
If you like to understand better what open and readline does look at Python doc input output, the split command is explained in the Python doc on strings
Comments
You can also use Python's csv module. If your data is in a .csv file and you have uploaded it to the notebook, you can do something like:
import csv
data =list( csv.reader(open(DATA+'DataFile.csv','rU')) )
data = map(lambda x: [float(x[0]),float(x[1])],data)
list_plot(data)
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Asked: 2012-10-05 06:28:03 +0100
Seen: 6,330 times
Last updated: Oct 05 '12
