The open() Function

The open() function opens the given file in the given mode (read, write, append) and returns a file object.

file = open(filename, "r")    # read
file = open(filename, "w")    # write
file = open(filename, "a")    # append
file = open(filename, "r+")   # read + write
file = open(filename, "w+")   # read + write (new / cleared file)
file = open(filename, "a+")   # read + append (position starts at end of file)