String formatting issue (parantheses vs underline)

Question

I got a text file containing all my data

data = \'B:/tempfiles/bla.dat\'

from the text file I\'m listing the column header and their types with

Answer 1

The behaviour is documented, the NameValidator class in lib/_iotools.py which parses the names passed in to genfromtxt:

class NameValidator(object):
    """
    Object to validate a list of strings to use as field names.
    The strings are stripped of any non alphanumeric character, and spaces
    are replaced by '_'. During instantiation, the user can define a list
    of names to exclude, as well as a list of invalid characters. Names in
    the exclusion list are appended a '_' character.
    Once an instance has been created, it can be called with a list of
    names, and a list of valid names will be created.  The `__call__`
    method accepts an optional keyword "default" that sets the default name
    in case of ambiguity. By default this is 'f', so that names will
    default to `f0`, `f1`, etc.

The relevant line in your case being The strings are stripped of any non alphanumeric character

You can see the behaviour by calling the NameValidator.validate on a list with other non alphanumeric characters in the names:

In [17]: from numpy.lib._iotools import NameValidator

In [18]: l = ["foo(1)","bar!!!","foo bar??"]

In [19]: NameValidator().validate(l)
Out[19]: ('foo1', 'bar', 'foo_bar')

And the same using genfromtxt:

In [24]: datafile = np.genfromtxt("foo.txt", dtype=[('foo!! bar??', '