how to use tempfile.NamedTemporaryFile() in python

This could be one of two reasons:

Firstly, by default the temporary file is deleted as soon as it is closed. To fix this use:

tf = tempfile.NamedTemporaryFile(delete=False)

and then delete the file manually once you've finished viewing it in the other application.

Alternatively, it could be that because the file is still open in Python Windows won't let you open it using another application.

You can also use it with a context manager so that the file will be closed/deleted when it goes out of scope. It will also be cleaned up if the code in the context manager raises.

import tempfilewith tempfile.NamedTemporaryFile() as temp:    temp.write('Some data')    temp.flush()    # do something interesting with temp before it is destroyed

Here is a useful context manager for this.(In my opinion, this functionality should be part of the Python standard library.)

# python2 or python3import contextlibimport os@contextlib.contextmanagerdef temporary_filename(suffix=None):  """Context that introduces a temporary file.  Creates a temporary file, yields its name, and upon context exit, deletes it.  (In contrast, tempfile.NamedTemporaryFile() provides a 'file' object and  deletes the file as soon as that file object is closed, so the temporary file  cannot be safely re-opened by another library or process.)  Args:    suffix: desired filename extension (e.g. '.mp4').  Yields:    The name of the temporary file.  """  import tempfile  try:    f = tempfile.NamedTemporaryFile(suffix=suffix, delete=False)    tmp_name = f.name    f.close()    yield tmp_name  finally:    os.unlink(tmp_name)# Example:with temporary_filename() as filename:  os.system('echo Hello >' + filename)  assert 6 <= os.path.getsize(filename) <= 8  # depending on text EOLassert not os.path.exists(filename)