Input and Output
================

To be exhaustive, here are some information about input and output in
Python. Since we will use the Numpy methods to read and write files,
**you may skip this chapter at first reading**.

We write or read **strings** to/from files (other types must be converted to
strings). To write in a file::

    >>> f = open('workfile', 'w') # opens the workfile file
    >>> type(f)    # doctest: +SKIP 
    <type 'file'>
    >>> f.write('This is a test \nand another test')   # doctest: +SKIP 
    >>> f.close()

To read from a file

.. sourcecode:: ipython

    In [1]: f = open('workfile', 'r')

    In [2]: s = f.read()

    In [3]: print(s)
    This is a test 
    and another test

    In [4]: f.close()


.. seealso::
   
   For more details: https://docs.python.org/tutorial/inputoutput.html

Iterating over a file
~~~~~~~~~~~~~~~~~~~~~

.. sourcecode:: ipython

    In [6]: f = open('workfile', 'r')

    In [7]: for line in f:
       ...:     print(line)
       ...:
    This is a test 

    and another test

    In [8]: f.close()

File modes
----------

* Read-only: ``r``
* Write-only: ``w``

  * Note: Create a new file or *overwrite* existing file.

* Append a file: ``a``
* Read and Write: ``r+``
* Binary mode: ``b``

  * Note: Use for binary files, especially on Windows.