create & read from tempfile

Complete example.

import tempfile
with tempfile.NamedTemporaryFile() as temp:
    temp.write('Some data')
    if should_call_some_python_function_that_will_read_the_file():
       temp.seek(0)
       some_python_function(temp)
    elif should_call_external_command():
       temp.flush()
       subprocess.call(["wc", temp.name])

Update: As mentioned in the comments, this may not work in windows. Use this solution for windows

Update 2: Python3 requires that the string to be written is represented as bytes, not str, so do instead

temp.write(bytes('Some data', encoding = 'utf-8'))