How to import a (MATLAB) .mat file into Python?

Post date: Aug 30, 2012 4:01:06 AM

Q: How to import a (MATLAB) .mat file into Python?

A: The .mat file will be imported into Python in the form of dictionary, using the function loadmat in the package scipy.io.

In this example below, we import easymatfile.mat into dictionary x.

'''This code shows how to import .mat file (MATLAB format) into dictionary using scipy.io'''

# First we will import the scipy.io

import scipy.io

# load .mat file into dictionary x

x = scipy.io.loadmat('/home/bot/Dropbox/course_work/python_study/fMRI_basic/easymatfile.mat')

# easymatfile.mat contains 3 matlab variables

# a: [10x30]

# b: [20x100]

# c: [1x1]

# in order to get a, b and c we say

pyA = x['a']

pyB = x['b']

pyC = x['c']

# Now we want plot the figures

from pylab import *

from matplotlib import *

matshow(pyA,1)

matshow(pyB,2)

matshow(pyC,3)

# Now, we will show all three figures

show()

In IDLE workspace, you will find that x is a dictionary with 'a', 'b' and 'c' and the keys. Also, you will some additional keys '__header__', '__globals__' and '__version__'.

>>> x

{'a': some 10x30 array ,

  'c': array([[ 1.2]]),

  'b': some 20 x 100 array,

  '__header__': 'MATLAB 5.0 MAT-file, Platform: GLNXA64, Created on: Wed Aug 29 20:19:01 2012',

  '__globals__': [],

  '__version__': '1.0'}