def test_read_columns(self):
"""Test basic column reading."""
fn = self.filenames[0]
# Get the first two columns. Both columns are of type int.
col0, col1 = du.read_columns(fn, self.header_lines[fn], (int, int))
self.assertEqual(col0, self.columns[fn][0])
self.assertEqual(col1, self.columns[fn][1])
# Read columns 1 and 3 and convert them to type
# int and float, respectively. Skip the two header rows.
col1, col3 = du.read_columns(fn, self.header_lines[fn], (int, float), (1,3))
self.assertEqual(col1, self.columns[fn][1])
self.assertEqual(col3, self.columns[fn][3])
# Read only the second column. Note the use of tuples!
col1, = du.read_columns(fn, self.header_lines[fn], (int,), (1,))
self.assertEqual(col1, self.columns[fn][1])
# A missing column should raise IndexError.
fn = self.filenames[1]
self.assertRaises(IndexError, du.read_columns,
fn, self.header_lines[fn], (int,float), (1,3))
# Finding a float when int is expected should raise
# ValueError.
fn = self.filenames[2]
self.assertRaises(ValueError, du.read_columns,
fn, self.header_lines[fn], (int,int), (0,1))
def test_read_columns_fun(self):
"""Test column reading with conversion function."""
fn = self.filenames[0]
# Get the first two columns. Both columns are of type int.
def col_fun(fields):
return int(fields[0]), int(fields[1])
col0, col1 = du.read_columns(fn, self.header_lines[fn], col_fun)
self.assertEqual(col0, self.columns[fn][0])
self.assertEqual(col1, self.columns[fn][1])
# Read columns 1 and 3 and convert them to type
# int and float, respectively. Skip the two header rows.
def col_fun(fields):
return int(fields[1]), float(fields[3])
col1, col3 = du.read_columns(fn, self.header_lines[fn], col_fun)
self.assertEqual(col1, self.columns[fn][1])
self.assertEqual(col3, self.columns[fn][3])
# Read only the second column. Note the use of tuples!
def col_fun(fields):
return int(fields[1]),
col1, = du.read_columns(fn, self.header_lines[fn], col_fun)
self.assertEqual(col1, self.columns[fn][1])
