Reading mat files

Date:2017-07-31 (last modified), 2008-04-02 (created)

Here are examples of how to read two variables lat and lon from a mat file called "test.mat".

= Matlab up to 7.1 = mat files created with Matlab up to version 7.1 can be read using the mio module part of Reading structures (and arrays of structures) is supported, elements are accessed with the same syntax as in Matlab: after reading a structure called e.g. struct, its lat element can be obtained with, or struct.__getattribute__('lat') if the element name comes from a string.

In [ ]:
#!/usr/bin/env python
from import loadmat
x = loadmat('test.mat')
lon = x['lon']
lat = x['lat']
# one-liner to read a single variable
lon = loadmat('test.mat')['lon']

Matlab 7.3 and greater

Beginning at release 7.3 of Matlab, mat files are actually saved using the HDF5 format by default (except if you use the -vX flag at save time, see in Matlab). These files can be read in Python using, for instance, the PyTables or h5py package. Reading Matlab structures in mat files does not seem supported at this point.

In [ ]:
#!/usr/bin/env python
import tables
file = tables.openFile('test.mat')
lon = file.root.lon[:]
lat =[:]
# Alternate syntax if the variable name is in a string
varname = 'lon'
lon = file.getNode('/' + varname)[:]

Section author: Unknown[16], DavidPowell, srvanrell