importing with .m instead of .py

W

Wanderer

I would like to import Matlab/Octave files of the .m sort into Python
that look like this.

# comment
y=[1,2,3,4,5\
,6,7,8,9];
# comment

The only problem is I have to change the extensions from .m to .py. Is
there a way to get python to import files that don't end in .py?

Thank you
 
C

Cesar Koers

Wanderer said:
I would like to import Matlab/Octave files of the .m sort into Python
that look like this.

# comment
y=[1,2,3,4,5\
,6,7,8,9];
# comment

The only problem is I have to change the extensions from .m to .py. Is
there a way to get python to import files that don't end in .py?

Thank you
Hi,

(untested:) read the .m file as a string, then evaluate the string (see
eval()) in appropriate context?


success!

bye
 
I

Ishwor Gurung

Wanderer
Hi
Refer to http://docs.python.org/tutorial/modules.html#the-module-search-path.

Particularly-
"
When a module named spam is imported, the interpreter searches for a
file named spam.py in the current directory, and then in the list of
directories specified by the environment variable PYTHONPATH. This has
the same syntax as the shell variable PATH, that is, a list of
directory names. When PYTHONPATH is not set, or when the file is not
found there, the search continues in an installation-dependent default
path; on Unix, this is usually .:/usr/local/lib/python.
"

Having said that, please see below.
I would like to import Matlab/Octave files of the .m sort into Python
that look like this.

# comment
y=[1,2,3,4,5\
,6,7,8,9];
# comment

The only problem is I have to change the extensions from .m to .py. Is
there a way to get python to import files that don't end in .py?

You can try this for single file. Pretty trivial-
$ cat foo.m
y=[1,2,3]
$ export PYTHONSTARTUP=foo.m
$ python
Python 2.6.1 (r261:826, Sep 17 2009, 01:16:52)
[GCC 4.3.2] on linux2
[Unladen Swallow 2009Q3]
Type "help", "copyright", "credits" or "license" for more information.
dir() ['__builtins__', '__doc__', '__name__', '__package__', 'y']
y
[1, 2, 3]

Another way:.... print i
....
y=[1,2,3]

Another way:
import os;
matlab_files=[];
for root, dirs, files in os.walk('.'):
.... for i in files:
.... if i.endswith(".m"):
.... matlab_files.append(i);
....
matlab_files ['foo.m', 'bar.m']
for x in matlab_files: .... execfile(x);
dir()
['__builtins__', '__doc__', '__name__', 'dirs', 'files', 'i',
'matlab_files', 'os', 'root', 'x', 'y', 'z']
[3, 2, 1]

$ cat foo.m
y=[1,2,3]
$ cat bar.m
z=[3,2,1]

These sort of task are pretty trivial to do. You should take some time
to read through the documentation.. and oh don't be such a wanderer
loosing sight of such good resource such as http://docs.python.org :)
 
W

Wanderer

Wanderer
Hi
Refer tohttp://docs.python.org/tutorial/modules.html#the-module-search-path.

Particularly-
"
When a module named spam is imported, the interpreter searches for a
file named spam.py in the current directory, and then in the list of
directories specified by the environment variable PYTHONPATH. This has
the same syntax as the shell variable PATH, that is, a list of
directory names. When PYTHONPATH is not set, or when the file is not
found there, the search continues in an installation-dependent default
path; on Unix, this is usually .:/usr/local/lib/python.
"

Having said that, please see below.
I would like to import Matlab/Octave files of the .m sort into Python
that look like this.
# comment
y=[1,2,3,4,5\
,6,7,8,9];
# comment
The only problem is I have to change the extensions from .m to .py. Is
there a way to get python to import files that don't end in .py?

You can try this for single file. Pretty trivial-
$ cat foo.m
y=[1,2,3]
$ export PYTHONSTARTUP=foo.m
$ python
Python 2.6.1 (r261:826, Sep 17 2009, 01:16:52)
[GCC 4.3.2] on linux2
[Unladen Swallow 2009Q3]
Type "help", "copyright", "credits" or "license" for more information.>>> dir()

['__builtins__', '__doc__', '__name__', '__package__', 'y']>>> y

[1, 2, 3]

Another way:>>> f_ = open('foo.m','r');
...     print i
...
y=[1,2,3]

Another way:>>> import os;
matlab_files=[];
for root, dirs, files in os.walk('.'):

...     for i in files:
...             if i.endswith(".m"):
...                     matlab_files.append(i);
...>>> matlab_files
['foo.m', 'bar.m']
...     execfile(x);>>> dir()

['__builtins__', '__doc__', '__name__', 'dirs', 'files', 'i',
'matlab_files', 'os', 'root', 'x', 'y', 'z']>>> x
'b.m'

[3, 2, 1]

$ cat foo.m
y=[1,2,3]
$ cat bar.m
z=[3,2,1]

These sort of task are pretty trivial to do. You should take some time
to read through the documentation.. and oh don't be such a wanderer
loosing sight of such good resource such ashttp://docs.python.org:)

execfile(x) does what I'm looking for.

Thanks
 
W

Wanderer

Perhaps you are looking for Python import hook:http://www.python.org/dev/peps/pep-0302/

In you import hook you can do everything (and locate/import file with
any extension :)

I'm just porting a bunch of octave functions into pylab that use data
I collected in files like I show above. The execfile() method lets me
verify I get the same results in Octave and Python. It is in the NumPy
for Matlab users page at Mathesaurus http://mathesaurus.sourceforge.net/matlab-numpy.html,
but they make it look like it needs a .py extension. Like Ishwor said
'Trivial', now that I know how :)
 
W

wisccal

Wanderer said:
Is there a way to get python to import files that don't end in .py?

How about using imp.load_source?

y@x:/tmp$ cat out.m
print("this is my module")
# comment
y=[1,2,3,4,5,6,7,8,9];
# comment
y@x:/tmp$ cat load_my_module.py
import imp
MyModule=imp.load_source('MyModule','out.m')
print("y is {0}".format(MyModule.y))
y@x:/tmp$ p31 load_my_module.py
this is my module
y is [1, 2, 3, 4, 5, 6, 7, 8, 9]

Regards
wisccal
http://skre.ch
 

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