To allow us to interact with the filesystem, Python provides us with the built-in open function. This function can be invoked to open a file and return an object file. The latter allows us to perform various operations on the file, such as reading and writing. When we have finished interacting with the file, we must finally remember to close it by using the file.close method:

>>> f = open ('test.txt', 'w') # open the file for writing
>>> f.write ('first line of file  n') # write a line in file
>>> f.write ('second line of file  n') # write another line in file
>>> f.close () # we close the file
>>> f = open ('test.txt') # reopen the file for reading
>>> content = f.read () # read all the contents of the file
>>> print (content)
first line of the file
second line of the file
>>> f.close () # close the file