.. DO NOT EDIT.
.. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY.
.. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE:
.. "gallery/recipes/common_date_problems.py"
.. LINE NUMBERS ARE GIVEN BELOW.

.. only:: html

    .. note::
        :class: sphx-glr-download-link-note

        Click :ref:`here <sphx_glr_download_gallery_recipes_common_date_problems.py>`
        to download the full example code

.. rst-class:: sphx-glr-example-title

.. _sphx_glr_gallery_recipes_common_date_problems.py:


Fixing common date annoyances
=============================

Matplotlib allows you to natively plots python datetime instances, and
for the most part does a good job picking tick locations and string
formats.  There are a couple of things it does not handle so
gracefully, and here are some tricks to help you work around them.
We'll load up some sample date data which contains datetime.date
objects in a numpy record array::

  In [63]: datafile = cbook.get_sample_data('goog.npz')

  In [64]: r = np.load(datafile)['price_data'].view(np.recarray)

  In [65]: r.dtype
  Out[65]: dtype([('date', '<M8[D]'), ('', '|V4'), ('open', '<f8'),
                  ('high', '<f8'), ('low', '<f8'), ('close', '<f8'),
                  ('volume', '<i8'),  ('adj_close', '<f8')])

  In [66]: r.date
  Out[66]:
  array(['2004-08-19', '2004-08-20', '2004-08-23', ..., '2008-10-10',
         '2008-10-13', '2008-10-14'], dtype='datetime64[D]')

The dtype of the NumPy record array for the field ``date`` is ``datetime64[D]``
which means it is a 64-bit `numpy.datetime64` in 'day' units.

If you plot the data, ::

  In [67]: plot(r.date, r.close)
  Out[67]: [<matplotlib.lines.Line2D object at 0x92a6b6c>]

you will see that the x tick labels are all squashed together.

.. GENERATED FROM PYTHON SOURCE LINES 36-48

.. code-block:: default

    import matplotlib.cbook as cbook
    import matplotlib.dates as mdates
    import numpy as np
    import matplotlib.pyplot as plt

    r = (cbook.get_sample_data('goog.npz', np_load=True)['price_data']
         .view(np.recarray))

    fig, ax = plt.subplots()
    ax.plot(r.date, r.close)
    ax.set_title('Default date handling can cause overlapping labels')




.. image:: /gallery/recipes/images/sphx_glr_common_date_problems_001.png
    :alt: Default date handling can cause overlapping labels
    :class: sphx-glr-single-img


.. rst-class:: sphx-glr-script-out

 Out:

 .. code-block:: none


    Text(0.5, 1.0, 'Default date handling can cause overlapping labels')



.. GENERATED FROM PYTHON SOURCE LINES 49-60

Another annoyance is that if you hover the mouse over the window and look in
the lower right corner of the Matplotlib toolbar (:ref:`navigation-toolbar`)
at the x and y coordinates, you see that the x locations are formatted the
same way the tick labels are, e.g.,  "Dec 2004".

What we'd like is for the location in the toolbar to have a higher degree of
precision, e.g., giving us the exact date out mouse is hovering over.  To fix
the first problem, we can use `.Figure.autofmt_xdate` and to fix the second
problem we can use the ``ax.fmt_xdata`` attribute which can be set to any
function that takes a scalar and returns a string.  Matplotlib has a number
of date formatters built in, so we'll use one of those.

.. GENERATED FROM PYTHON SOURCE LINES 60-69

.. code-block:: default


    fig, ax = plt.subplots()
    ax.plot(r.date, r.close)
    # Rotate and align the tick labels so they look better.
    fig.autofmt_xdate()
    # Use a more precise date string for the x axis locations in the toolbar.
    ax.fmt_xdata = mdates.DateFormatter('%Y-%m-%d')
    ax.set_title('fig.autofmt_xdate fixes the labels')




.. image:: /gallery/recipes/images/sphx_glr_common_date_problems_002.png
    :alt: fig.autofmt_xdate fixes the labels
    :class: sphx-glr-single-img


.. rst-class:: sphx-glr-script-out

 Out:

 .. code-block:: none


    Text(0.5, 1.0, 'fig.autofmt_xdate fixes the labels')



.. GENERATED FROM PYTHON SOURCE LINES 70-72

Now when you hover your mouse over the plotted data, you'll see date
format strings like 2004-12-01 in the toolbar.

.. GENERATED FROM PYTHON SOURCE LINES 72-74

.. code-block:: default


    plt.show()








.. _sphx_glr_download_gallery_recipes_common_date_problems.py:


.. only :: html

 .. container:: sphx-glr-footer
    :class: sphx-glr-footer-example



  .. container:: sphx-glr-download sphx-glr-download-python

     :download:`Download Python source code: common_date_problems.py <common_date_problems.py>`



  .. container:: sphx-glr-download sphx-glr-download-jupyter

     :download:`Download Jupyter notebook: common_date_problems.ipynb <common_date_problems.ipynb>`


.. only:: html

 .. rst-class:: sphx-glr-signature

    Keywords: matplotlib code example, codex, python plot, pyplot
    `Gallery generated by Sphinx-Gallery
    <https://sphinx-gallery.readthedocs.io>`_