.. only:: html

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

        Click :ref:`here <sphx_glr_download_gallery_lines_bars_and_markers_markevery_demo.py>`     to download the full example code
    .. rst-class:: sphx-glr-example-title

    .. _sphx_glr_gallery_lines_bars_and_markers_markevery_demo.py:


==============
Markevery Demo
==============

This example demonstrates the various options for showing a marker at a
subset of data points using the ``markevery`` property of a Line2D object.

Integer arguments are fairly intuitive.  e.g. ``markevery=5`` will plot every
5th marker starting from the first data point.

Float arguments allow markers to be spaced at approximately equal distances
along the line.  The theoretical distance along the line between markers is
determined by multiplying the display-coordinate distance of the axes
bounding-box diagonal by the value of ``markevery``.  The data points closest
to the theoretical distances will be shown.

A slice or list/array can also be used with ``markevery`` to specify the
markers to show.


.. code-block:: default


    import numpy as np
    import matplotlib.pyplot as plt

    # define a list of markevery cases to plot
    cases = [None,
             8,
             (30, 8),
             [16, 24, 30], [0, -1],
             slice(100, 200, 3),
             0.1, 0.3, 1.5,
             (0.0, 0.1), (0.45, 0.1)]

    # define the figure size and grid layout properties
    figsize = (10, 8)
    cols = 3
    rows = len(cases) // cols + 1
    # define the data for cartesian plots
    delta = 0.11
    x = np.linspace(0, 10 - 2 * delta, 200) + delta
    y = np.sin(x) + 1.0 + delta


    def trim_axs(axs, N):
        """
        Reduce *axs* to *N* Axes. All further Axes are removed from the figure.
        """
        axs = axs.flat
        for ax in axs[N:]:
            ax.remove()
        return axs[:N]








Plot each markevery case for linear x and y scales


.. code-block:: default


    axs = plt.figure(figsize=figsize, constrained_layout=True).subplots(rows, cols)
    axs = trim_axs(axs, len(cases))
    for ax, case in zip(axs, cases):
        ax.set_title('markevery=%s' % str(case))
        ax.plot(x, y, 'o', ls='-', ms=4, markevery=case)




.. image:: /gallery/lines_bars_and_markers/images/sphx_glr_markevery_demo_001.png
    :alt: markevery=None, markevery=8, markevery=(30, 8), markevery=[16, 24, 30], markevery=[0, -1], markevery=slice(100, 200, 3), markevery=0.1, markevery=0.3, markevery=1.5, markevery=(0.0, 0.1), markevery=(0.45, 0.1)
    :class: sphx-glr-single-img





Plot each markevery case for log x and y scales


.. code-block:: default


    axs = plt.figure(figsize=figsize, constrained_layout=True).subplots(rows, cols)
    axs = trim_axs(axs, len(cases))
    for ax, case in zip(axs, cases):
        ax.set_title('markevery=%s' % str(case))
        ax.set_xscale('log')
        ax.set_yscale('log')
        ax.plot(x, y, 'o', ls='-', ms=4, markevery=case)




.. image:: /gallery/lines_bars_and_markers/images/sphx_glr_markevery_demo_002.png
    :alt: markevery=None, markevery=8, markevery=(30, 8), markevery=[16, 24, 30], markevery=[0, -1], markevery=slice(100, 200, 3), markevery=0.1, markevery=0.3, markevery=1.5, markevery=(0.0, 0.1), markevery=(0.45, 0.1)
    :class: sphx-glr-single-img





Plot each markevery case for linear x and y scales but zoomed in
note the behaviour when zoomed in.  When a start marker offset is specified
it is always interpreted with respect to the first data point which might be
different to the first visible data point.


.. code-block:: default


    axs = plt.figure(figsize=figsize, constrained_layout=True).subplots(rows, cols)
    axs = trim_axs(axs, len(cases))
    for ax, case in zip(axs, cases):
        ax.set_title('markevery=%s' % str(case))
        ax.plot(x, y, 'o', ls='-', ms=4, markevery=case)
        ax.set_xlim((6, 6.7))
        ax.set_ylim((1.1, 1.7))

    # define data for polar plots
    r = np.linspace(0, 3.0, 200)
    theta = 2 * np.pi * r




.. image:: /gallery/lines_bars_and_markers/images/sphx_glr_markevery_demo_003.png
    :alt: markevery=None, markevery=8, markevery=(30, 8), markevery=[16, 24, 30], markevery=[0, -1], markevery=slice(100, 200, 3), markevery=0.1, markevery=0.3, markevery=1.5, markevery=(0.0, 0.1), markevery=(0.45, 0.1)
    :class: sphx-glr-single-img





Plot each markevery case for polar plots


.. code-block:: default


    axs = plt.figure(figsize=figsize, constrained_layout=True).subplots(
        rows, cols, subplot_kw={'projection': 'polar'})
    axs = trim_axs(axs, len(cases))
    for ax, case in zip(axs, cases):
        ax.set_title('markevery=%s' % str(case))
        ax.plot(theta, r, 'o', ls='-', ms=4, markevery=case)

    plt.show()



.. image:: /gallery/lines_bars_and_markers/images/sphx_glr_markevery_demo_004.png
    :alt: markevery=None, markevery=8, markevery=(30, 8), markevery=[16, 24, 30], markevery=[0, -1], markevery=slice(100, 200, 3), markevery=0.1, markevery=0.3, markevery=1.5, markevery=(0.0, 0.1), markevery=(0.45, 0.1)
    :class: sphx-glr-single-img






.. rst-class:: sphx-glr-timing

   **Total running time of the script:** ( 0 minutes  12.943 seconds)


.. _sphx_glr_download_gallery_lines_bars_and_markers_markevery_demo.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: markevery_demo.py <markevery_demo.py>`



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

     :download:`Download Jupyter notebook: markevery_demo.ipynb <markevery_demo.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>`_