.. only:: html .. note:: :class: sphx-glr-download-link-note Click :ref:`here ` to download the full example code .. rst-class:: sphx-glr-example-title .. _sphx_glr_gallery_ticks_and_spines_date_concise_formatter.py: ================================================ Formatting date ticks using ConciseDateFormatter ================================================ Finding good tick values and formatting the ticks for an axis that has date data is often a challenge. `~.dates.ConciseDateFormatter` is meant to improve the strings chosen for the ticklabels, and to minimize the strings used in those tick labels as much as possible. .. note:: This formatter is a candidate to become the default date tick formatter in future versions of Matplotlib. Please report any issues or suggestions for improvement to the github repository or mailing list. .. code-block:: default import datetime import matplotlib.pyplot as plt import matplotlib.dates as mdates import numpy as np First, the default formatter. .. code-block:: default base = datetime.datetime(2005, 2, 1) dates = np.array([base + datetime.timedelta(hours=(2 * i)) for i in range(732)]) N = len(dates) np.random.seed(19680801) y = np.cumsum(np.random.randn(N)) fig, axs = plt.subplots(3, 1, constrained_layout=True, figsize=(6, 6)) lims = [(np.datetime64('2005-02'), np.datetime64('2005-04')), (np.datetime64('2005-02-03'), np.datetime64('2005-02-15')), (np.datetime64('2005-02-03 11:00'), np.datetime64('2005-02-04 13:20'))] for nn, ax in enumerate(axs): ax.plot(dates, y) ax.set_xlim(lims[nn]) # rotate_labels... for label in ax.get_xticklabels(): label.set_rotation(40) label.set_horizontalalignment('right') axs[0].set_title('Default Date Formatter') plt.show() .. image:: /gallery/ticks_and_spines/images/sphx_glr_date_concise_formatter_001.png :class: sphx-glr-single-img The default date formater is quite verbose, so we have the option of using `~.dates.ConciseDateFormatter`, as shown below. Note that for this example the labels do not need to be rotated as they do for the default formatter because the labels are as small as possible. .. code-block:: default fig, axs = plt.subplots(3, 1, constrained_layout=True, figsize=(6, 6)) for nn, ax in enumerate(axs): locator = mdates.AutoDateLocator(minticks=3, maxticks=7) formatter = mdates.ConciseDateFormatter(locator) ax.xaxis.set_major_locator(locator) ax.xaxis.set_major_formatter(formatter) ax.plot(dates, y) ax.set_xlim(lims[nn]) axs[0].set_title('Concise Date Formatter') plt.show() .. image:: /gallery/ticks_and_spines/images/sphx_glr_date_concise_formatter_002.png :class: sphx-glr-single-img If all calls to axes that have dates are to be made using this converter, it is probably most convenient to use the units registry where you do imports: .. code-block:: default import matplotlib.units as munits converter = mdates.ConciseDateConverter() munits.registry[np.datetime64] = converter munits.registry[datetime.date] = converter munits.registry[datetime.datetime] = converter fig, axs = plt.subplots(3, 1, figsize=(6, 6), constrained_layout=True) for nn, ax in enumerate(axs): ax.plot(dates, y) ax.set_xlim(lims[nn]) axs[0].set_title('Concise Date Formatter') plt.show() .. image:: /gallery/ticks_and_spines/images/sphx_glr_date_concise_formatter_003.png :class: sphx-glr-single-img Localization of date formats ============================ Dates formats can be localized if the default formats are not desirable by manipulating one of three lists of strings. The ``formatter.formats`` list of formats is for the normal tick labels, There are six levels: years, months, days, hours, minutes, seconds. The ``formatter.offset_formats`` is how the "offset" string on the right of the axis is formatted. This is usually much more verbose than the tick labels. Finally, the ``formatter.zero_formats`` are the formats of the ticks that are "zeros". These are tick values that are either the first of the year, month, or day of month, or the zeroth hour, minute, or second. These are usually the same as the format of the ticks a level above. For example if the axis limits mean the ticks are mostly days, then we label 1 Mar 2005 simply with a "Mar". If the axis limits are mostly hours, we label Feb 4 00:00 as simply "Feb-4". Note that these format lists can also be passed to `.ConciseDateFormatter` as optional kwargs. Here we modify the labels to be "day month year", instead of the ISO "year month day": .. code-block:: default fig, axs = plt.subplots(3, 1, constrained_layout=True, figsize=(6, 6)) for nn, ax in enumerate(axs): locator = mdates.AutoDateLocator() formatter = mdates.ConciseDateFormatter(locator) formatter.formats = ['%y', # ticks are mostly years '%b', # ticks are mostly months '%d', # ticks are mostly days '%H:%M', # hrs '%H:%M', # min '%S.%f', ] # secs # these are mostly just the level above... formatter.zero_formats = [''] + formatter.formats[:-1] # ...except for ticks that are mostly hours, then it is nice to have # month-day: formatter.zero_formats[3] = '%d-%b' formatter.offset_formats = ['', '%Y', '%b %Y', '%d %b %Y', '%d %b %Y', '%d %b %Y %H:%M', ] ax.xaxis.set_major_locator(locator) ax.xaxis.set_major_formatter(formatter) ax.plot(dates, y) ax.set_xlim(lims[nn]) axs[0].set_title('Concise Date Formatter') plt.show() .. image:: /gallery/ticks_and_spines/images/sphx_glr_date_concise_formatter_004.png :class: sphx-glr-single-img Registering a converter with localization ========================================= `.ConciseDateFormatter` doesn't have rcParams entries, but localization can be accomplished by passing kwargs to `~.ConciseDateConverter` and registering the datatypes you will use with the units registry: .. code-block:: default import datetime formats = ['%y', # ticks are mostly years '%b', # ticks are mostly months '%d', # ticks are mostly days '%H:%M', # hrs '%H:%M', # min '%S.%f', ] # secs # these can be the same, except offset by one level.... zero_formats = [''] + formats[:-1] # ...except for ticks that are mostly hours, then its nice to have month-day zero_formats[3] = '%d-%b' offset_formats = ['', '%Y', '%b %Y', '%d %b %Y', '%d %b %Y', '%d %b %Y %H:%M', ] converter = mdates.ConciseDateConverter(formats=formats, zero_formats=zero_formats, offset_formats=offset_formats) munits.registry[np.datetime64] = converter munits.registry[datetime.date] = converter munits.registry[datetime.datetime] = converter fig, axs = plt.subplots(3, 1, constrained_layout=True, figsize=(6, 6)) for nn, ax in enumerate(axs): ax.plot(dates, y) ax.set_xlim(lims[nn]) axs[0].set_title('Concise Date Formatter registered non-default') plt.show() .. image:: /gallery/ticks_and_spines/images/sphx_glr_date_concise_formatter_005.png :class: sphx-glr-single-img .. _sphx_glr_download_gallery_ticks_and_spines_date_concise_formatter.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: date_concise_formatter.py ` .. container:: sphx-glr-download sphx-glr-download-jupyter :download:`Download Jupyter notebook: date_concise_formatter.ipynb ` .. only:: html .. rst-class:: sphx-glr-signature Keywords: matplotlib code example, codex, python plot, pyplot `Gallery generated by Sphinx-Gallery `_