Simple function for reading in .mpt text files

This will be helpful for checking the data read in by the .mpr
file reader

BioLogic.py

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+# -*- coding: utf-8 -*-
+"""Code to read in data files from Bio-Logic instruments"""
+
+import re
+import csv
+
+
+def MPTfile(file_or_path):
+    """Simple function to open MPT files as csv.DictReader objects
+
+    Checks for the correct headings, skips any comments and returns a
+    csv.DictReader object and a list of comments
+    """
+
+    if isinstance(file_or_path, str):
+        mpt_file = open(file_or_path, 'r')
+    else:
+        mpt_file = file_or_path
+
+    magic = next(mpt_file)
+    if magic != 'EC-Lab ASCII FILE\n':
+        raise ValueError("Bad first line for EC-Lab file: '%s'" % magic)
+
+    nb_headers_match = re.match('Nb header lines : (\d+)', next(mpt_file))
+    nb_headers = int(nb_headers_match.group(1))
+    if nb_headers < 3:
+        raise ValueError("Too few header lines: %d" % nb_headers)
+
+    ## The 'magic number' line, the 'Nb headers' line and the column headers
+    ## make three lines. Every additional line is a comment line.
+    comments = [next(mpt_file) for i in range(nb_headers - 3)]
+
+    mpt_csv = csv.DictReader(mpt_file, dialect='excel-tab')
+
+    expected_fieldnames = (
+        ["mode", "ox/red", "error", "control changes", "Ns changes",
+         "counter inc.", "time/s", "control/V/mA", "Ewe/V", "dq/mA.h",
+         "P/W", "<I>/mA", "(Q-Qo)/mA.h", "x"],
+        ["mode", "ox/red", "error", "control changes", "Ns changes",
+         "counter inc.", "time/s", "control/V", "Ewe/V", "I/mA",
+         "dQ/mA.h", "P/W"],
+        ["mode", "ox/red", "error", "control changes", "Ns changes",
+         "counter inc.", "time/s", "control/V", "Ewe/V", "<I>/mA",
+         "dQ/mA.h", "P/W"])
+    if mpt_csv.fieldnames not in expected_fieldnames:
+        raise ValueError("Unrecognised headers for MPT file format")
+
+    return mpt_csv, comments

__init__.py

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+from .BioLogic import MPTfile

tests/test_BioLogic.py

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+# -*- coding: utf-8 -*-
+
+import os.path
+
+from nose.tools import ok_, eq_, raises
+
+from .. import MPTfile
+
+testdata_dir = os.path.join(os.path.dirname(__file__), 'testdata')
+
+
+def test_open_MPT():
+    mpt1, comments = MPTfile(os.path.join(testdata_dir, 'bio-logic1.mpt'))
+    eq_(comments, [])
+    eq_(mpt1.fieldnames, ["mode", "ox/red", "error", "control changes",
+                          "Ns changes", "counter inc.", "time/s",
+                          "control/V/mA", "Ewe/V", "dq/mA.h", "P/W",
+                          "<I>/mA", "(Q-Qo)/mA.h", "x"])
+
+
+@raises(ValueError)
+def test_open_MPT_fails_for_bad_file():
+    mpt1 = MPTfile(os.path.join(testdata_dir, 'bio-logic1.mpr'))