Useful Python Utils
==============================================================================

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Python Utils is a collection of small Python functions and
classes which make common patterns shorter and easier. It is by no means a
complete collection but it has served me quite a bit in the past and I will
keep extending it.

One of the libraries using Python Utils is Django Utils.

Documentation is available at: https://python-utils.readthedocs.org/en/latest/

Links
-----

 - The source: https://github.com/WoLpH/python-utils
 - Project page: https://pypi.python.org/pypi/python-utils
 - Reporting bugs: https://github.com/WoLpH/python-utils/issues
 - Documentation: https://python-utils.readthedocs.io/en/latest/
 - My blog: https://wol.ph/

Requirements for installing:
------------------------------------------------------------------------------

For the Python 3+ release (i.e. v3.0.0 or higher) there are no requirements.
For the Python 2 compatible version (v2.x.x) the `six` package is needed.

Installation:
------------------------------------------------------------------------------

The package can be installed through `pip` (this is the recommended method):

    pip install python-utils
    
Or if `pip` is not available, `easy_install` should work as well:

    easy_install python-utils
    
Or download the latest release from Pypi (https://pypi.python.org/pypi/python-utils) or Github.

Note that the releases on Pypi are signed with my GPG key (https://pgp.mit.edu/pks/lookup?op=vindex&search=0xE81444E9CE1F695D) and can be checked using GPG:

     gpg --verify python-utils-<version>.tar.gz.asc python-utils-<version>.tar.gz

Quickstart
------------------------------------------------------------------------------

This module makes it easy to execute common tasks in Python scripts such as
converting text to numbers and making sure a string is in unicode or bytes
format.

Examples
------------------------------------------------------------------------------

To easily retry a block of code with a configurable timeout, you can use the
`time.timeout_generator`:

.. code-block:: pycon

    >>> for i in time.timeout_generator(10):
    ...     try:
    ...         # Run your code here
    ...     except Exception as e:
    ...         # Handle the exception

Easy formatting of timestamps and calculating the time since:

.. code-block:: pycon

    >>> time.format_time('1')
    '0:00:01'
    >>> time.format_time(1.234)
    '0:00:01'
    >>> time.format_time(1)
    '0:00:01'
    >>> time.format_time(datetime.datetime(2000, 1, 2, 3, 4, 5, 6))
    '2000-01-02 03:04:05'
    >>> time.format_time(datetime.date(2000, 1, 2))
    '2000-01-02'
    >>> time.format_time(datetime.timedelta(seconds=3661))
    '1:01:01'
    >>> time.format_time(None)
    '--:--:--'

    >>> formatters.timesince(now)
    'just now'
    >>> formatters.timesince(now - datetime.timedelta(seconds=1))
    '1 second ago'
    >>> formatters.timesince(now - datetime.timedelta(seconds=2))
    '2 seconds ago'
    >>> formatters.timesince(now - datetime.timedelta(seconds=60))
    '1 minute ago'

Converting your test from camel-case to underscores:

.. code-block:: pycon

    >>> camel_to_underscore('SpamEggsAndBacon')
    'spam_eggs_and_bacon'

A convenient decorator to set function attributes using a decorator:

.. code-block:: pycon

    You can use:
    >>> @decorators.set_attributes(short_description='Name')
    ... def upper_case_name(self, obj):
    ...     return ("%s %s" % (obj.first_name, obj.last_name)).upper()

    Instead of:
    >>> def upper_case_name(obj):
    ...     return ("%s %s" % (obj.first_name, obj.last_name)).upper()

    >>> upper_case_name.short_description = 'Name'

Or to scale numbers:

.. code-block:: pycon

    >>> converters.remap(500, old_min=0, old_max=1000, new_min=0, new_max=100)
    50

    # Or with decimals:
    >>> remap(decimal.Decimal('250.0'), 0.0, 1000.0, 0.0, 100.0)
    Decimal('25.0')

To get the screen/window/terminal size in characters:

.. code-block:: pycon

    >>> terminal.get_terminal_size()
    (80, 24)

That method supports IPython and Jupyter as well as regular shells, using
`blessings` and other modules depending on what is available.

To extract a number from nearly every string:

.. code-block:: pycon

    >>> converters.to_int('spam15eggs')
    15
    >>> converters.to_int('spam')
    0
    >>> number = converters.to_int('spam', default=1)
    1

To do a global import programmatically you can use the `import_global`
function. This effectively emulates a `from ... import *`

.. code-block:: python

    from python_utils.import_ import import_global

    # The following is  the equivalent of `from some_module import *`
    import_global('some_module')

Or add a correclty named logger to your classes which can be easily accessed:

.. code-block:: python

    class MyClass(Logged):
        def __init__(self):
            Logged.__init__(self)

    my_class = MyClass()

    # Accessing the logging method:
    my_class.error('error')

    # With formatting:
    my_class.error('The logger supports %(formatting)s',
                   formatting='named parameters')

    # Or to access the actual log function (overwriting the log formatting can
    # be done n the log method)
    import logging
    my_class.log(logging.ERROR, 'log')

