NameError: name 'file' is not defined as an isinstance parameter

Question

I'm currently debugging a code and I've bumped into a "NameError: name 'file' is not defined" problem different from other entries, my problem is caused because the isinstance function doesn't understand the "file parameter"

def write_param_file(f, molfile, name, frag_id, base_confs, max_confs, amino_acid=None): #{{{
    '''Writes a Molfile object to a file.
    f may be a file name or file handle.
    base_confs is the number of heavy-atom conformations generated by e.g. Omega
    max_confs is the maximum number of conformations desired after adding proton rotation
        The total number of confs may still be larger than max_confs,
        but at least we'll skip -ex# extra sampling of proton chis.
    '''
    close_file = False
    if not isinstance(f, file):
        f = open(f, 'w')
        close_file = True

the isinstance function wants two arguments that must be tuples. And as you can see "f" is defined. But "file" is not. I think there is an easy solution to this problem so if you can help it would be very helpful.

Does this answer your question? Check if object is file-like in Python — rdas
– rdas, Commented Jan 19, 2021 at 11:40
another option is to check if the following is true type(f) is io.TextIOWrapper (this only works for reading in text mode, in binary mode its io.BufferedRead) — Nullman
– Nullman, Commented Jan 19, 2021 at 11:44
This error has nothing to do with the isinstance function, the error happens before that function is called, when the interpreter tries to resolve the name of the argument. file deosn't exist. Was this code written for Python 2? — juanpa.arrivillaga
– juanpa.arrivillaga, Commented Jan 19, 2021 at 11:46
In this case, you should probably just check if it is a string. — juanpa.arrivillaga
– juanpa.arrivillaga, Commented Jan 19, 2021 at 11:47

Pallie · Accepted Answer · 2021-01-19 13:19:44Z

0

File is an existing type in python 2 but not in python 3. Run this code with python 2 or adapt it with information from the link below.

isinstance file python 2.7 and 3.5

answered Jan 19, 2021 at 13:19

Pallie

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