Using Python to replace MATLAB: how to import data?

Question

I want to use some Python libraries to replace MATLAB. How could I import Excel data in Python (for example using NumPy) to use them?

I don't know if Python is a credible alternative to MATLAB, but I want to try it. Is there a a tutorial?

Solution 1

Depending on what kind of computations you are doing with MATLAB (and on which toolboxes you are using), Python could be a good alternative to MATLAB.

Python + NumPy + SciPy + Matplotlib are the right combination to start.

For the data, you can, for example, save your data directly in text file (assuming that you are not directly concerned by floating-point precision issues) and read it in Python.

If your data are Excel data, where each value is separated by a ";", you can for example read the file line by line, and use the split() method (with ";" as argument) to get each value.

For MATLAB up to version 7.1, it is possible to directly load .mat files from Python with the scipy.io.matlab.mio module.

Solution 2

Pandas is a Python data analysis library that can import/export from Excel pretty easily. Here's how to do it:

http://pandas.pydata.org/pandas-docs/stable/10min.html#excel

Crash course:

import pandas as pd
data = pd.read_excel('foo.xlsx', 'Sheet1', index_col=None, na_values=['NA'])

Solution 3

If you come from the MATLAB world, Pylab will ease your transition. Once you have converted your data to ASCII, pylab.load() will do the rest:

pylab.load(fname, comments='#', delimiter=None, converters=None, 
           skiprows=0, usecols=None, unpack=False, 
           dtype=<type 'numpy.float64'>)

Solution 4

There's Matplotlib for plots and the csv module for reading Excel data (assuming you can dump to CSV).

Here's a tutorial about replacing MATLAB with Python.

Solution 5

If you saved you data in MATLAB format, use:

from scipy.io import loadmat

datafile = "yourfile.mat"
data = loadmat(datafile, matlab_compatible=True)
var1 = data['nameOfYourVariable'].squeeze()
var2 = data['nameOfYourOtherVariable'].squeeze()

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Comments

[stephan]

SAGE (mentionend in the tutorial, see sagemath.org) is a pretty cool stack based on Python.

[Admin]

Thanx a lot. I'm going to try SAGE.