Docs build of 112a2257387b72490f7ab0e0b428a2abd2c39374

.buildinfo

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 # Sphinx build info version 1
 # This file hashes the configuration used when building these files. When it is not found, a full rebuild will be done.
-config: fee21aba0ad35d7353946075a94d4ae9
-tags: 645f666f9bcd5a90fca523b33c5a78b7
+config: ff8b33b6a61b259fdd4ffead4fdf31ca
+tags: 526838a1027dd1fd771fd21a9668211e

_downloads/0017d0c84e03d6c5e463e23d8e570671/line_collection.ipynb

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+{
+  "cells": [
+    {
+      "cell_type": "markdown",
+      "metadata": {},
+      "source": [
+        "\n# Plotting multiple lines with a LineCollection\n\nMatplotlib can efficiently draw multiple lines at once using a\n`~.LineCollection`, as showcased below.\n"
+      ]
+    },
+    {
+      "cell_type": "code",
+      "execution_count": null,
+      "metadata": {
+        "collapsed": false
+      },
+      "outputs": [],
+      "source": [
+        "import matplotlib.pyplot as plt\nimport numpy as np\n\nfrom matplotlib.collections import LineCollection\n\nx = np.arange(100)\n# Here are many sets of y to plot vs. x\nys = x[:50, np.newaxis] + x[np.newaxis, :]\n\nsegs = np.zeros((50, 100, 2))\nsegs[:, :, 1] = ys\nsegs[:, :, 0] = x\n\n# Mask some values to test masked array support:\nsegs = np.ma.masked_where((segs > 50) & (segs < 60), segs)\n\n# We need to set the plot limits, they will not autoscale\nfig, ax = plt.subplots()\nax.set_xlim(x.min(), x.max())\nax.set_ylim(ys.min(), ys.max())\n\n# *colors* is sequence of rgba tuples.\n# *linestyle* is a string or dash tuple. Legal string values are\n# solid|dashed|dashdot|dotted.  The dash tuple is (offset, onoffseq) where\n# onoffseq is an even length tuple of on and off ink in points.  If linestyle\n# is omitted, 'solid' is used.\n# See `matplotlib.collections.LineCollection` for more information.\ncolors = plt.rcParams['axes.prop_cycle'].by_key()['color']\n\nline_segments = LineCollection(segs, linewidths=(0.5, 1, 1.5, 2),\n                               colors=colors, linestyle='solid')\nax.add_collection(line_segments)\nax.set_title('Line collection with masked arrays')\nplt.show()"
+      ]
+    },
+    {
+      "cell_type": "markdown",
+      "metadata": {},
+      "source": [
+        "In the following example, instead of passing a list of colors\n(``colors=colors``), we pass an array of values (``array=x``) that get\ncolormapped.\n\n"
+      ]
+    },
+    {
+      "cell_type": "code",
+      "execution_count": null,
+      "metadata": {
+        "collapsed": false
+      },
+      "outputs": [],
+      "source": [
+        "N = 50\nx = np.arange(N)\nys = [x + i for i in x]  # Many sets of y to plot vs. x\nsegs = [np.column_stack([x, y]) for y in ys]\n\nfig, ax = plt.subplots()\nax.set_xlim(np.min(x), np.max(x))\nax.set_ylim(np.min(ys), np.max(ys))\n\nline_segments = LineCollection(segs, array=x,\n                               linewidths=(0.5, 1, 1.5, 2),\n                               linestyles='solid')\nax.add_collection(line_segments)\naxcb = fig.colorbar(line_segments)\naxcb.set_label('Line Number')\nax.set_title('Line Collection with mapped colors')\nplt.sci(line_segments)  # This allows interactive changing of the colormap.\nplt.show()"
+      ]
+    },
+    {
+      "cell_type": "markdown",
+      "metadata": {},
+      "source": [
+        ".. admonition:: References\n\n   The use of the following functions, methods, classes and modules is shown\n   in this example:\n\n   - `matplotlib.collections`\n   - `matplotlib.collections.LineCollection`\n   - `matplotlib.cm.ScalarMappable.set_array`\n   - `matplotlib.axes.Axes.add_collection`\n   - `matplotlib.figure.Figure.colorbar` / `matplotlib.pyplot.colorbar`\n   - `matplotlib.pyplot.sci`\n\n"
+      ]
+    }
+  ],
+  "metadata": {
+    "kernelspec": {
+      "display_name": "Python 3",
+      "language": "python",
+      "name": "python3"
+    },
+    "language_info": {
+      "codemirror_mode": {
+        "name": "ipython",
+        "version": 3
+      },
+      "file_extension": ".py",
+      "mimetype": "text/x-python",
+      "name": "python",
+      "nbconvert_exporter": "python",
+      "pygments_lexer": "ipython3",
+      "version": "3.9.18"
+    }
+  },
+  "nbformat": 4,
+  "nbformat_minor": 0
+}

_downloads/0058fbe25cf21cd7c40fb5bd22f92895/axes_units.ipynb

@@ -0,0 +1,266 @@
+{
+  "cells": [
+    {
+      "cell_type": "markdown",
+      "metadata": {},
+      "source": [
+        "\n\n# Plotting dates and strings\n\nThe most basic way to use Matplotlib plotting methods is to pass coordinates in\nas numerical numpy arrays.  For example, ``plot(x, y)`` will work if ``x`` and\n``y`` are numpy arrays of floats (or integers).  Plotting methods will also\nwork if `numpy.asarray` will convert ``x`` and ``y`` to an array of floating\npoint numbers; e.g. ``x`` could be a python list.\n\nMatplotlib also has the ability to convert other data types if a \"unit\nconverter\" exists for the data type.  Matplotlib has two built-in converters,\none for dates and the other for lists of strings.  Other downstream libraries\nhave their own converters to handle their data types.\n\nThe method to add converters to Matplotlib is described in `matplotlib.units`.\nHere we briefly overview the built-in date and string converters.\n\n## Date conversion\n\nIf ``x`` and/or ``y`` are a list of `datetime` or an array of\n`numpy.datetime64`, Matplotlib has a built-in converter that will convert the\ndatetime to a float, and add tick locators and formatters to the axis that are\nappropriate for dates.  See `matplotlib.dates`.\n\nIn the following example, the x-axis gains a converter that converts from\n`numpy.datetime64` to float, and a locator that put ticks at the beginning of\nthe month, and a formatter that label the ticks appropriately:\n"
+      ]
+    },
+    {
+      "cell_type": "code",
+      "execution_count": null,
+      "metadata": {
+        "collapsed": false
+      },
+      "outputs": [],
+      "source": [
+        "import numpy as np\n\nimport matplotlib.dates as mdates\nimport matplotlib.units as munits\n\nimport matplotlib.pyplot as plt\n\nfig, ax = plt.subplots(figsize=(5.4, 2), layout='constrained')\ntime = np.arange('1980-01-01', '1980-06-25', dtype='datetime64[D]')\nx = np.arange(len(time))\nax.plot(time, x)"
+      ]
+    },
+    {
+      "cell_type": "markdown",
+      "metadata": {},
+      "source": [
+        "Note that if we try to plot a float on the x-axis, it will be plotted in\nunits of days since the \"epoch\" for the converter, in this case 1970-01-01\n(see `date-format`).  So when we plot the value 0, the ticks start at\n1970-01-01.  (The locator also now chooses every two years for a tick instead\nof every month):\n\n"
+      ]
+    },
+    {
+      "cell_type": "code",
+      "execution_count": null,
+      "metadata": {
+        "collapsed": false
+      },
+      "outputs": [],
+      "source": [
+        "fig, ax = plt.subplots(figsize=(5.4, 2), layout='constrained')\ntime = np.arange('1980-01-01', '1980-06-25', dtype='datetime64[D]')\nx = np.arange(len(time))\nax.plot(time, x)\n# 0 gets labeled as 1970-01-01\nax.plot(0, 0, 'd')\nax.text(0, 0, ' Float x=0', rotation=45)"
+      ]
+    },
+    {
+      "cell_type": "markdown",
+      "metadata": {},
+      "source": [
+        "We can customize the locator and the formatter; see `date-locators` and\n`date-formatters` for a complete list, and\n`date_formatters_locators` for examples of them in use.  Here we locate\nby every second month, and format just with the month's 3-letter name using\n``\"%b\"`` (see `~datetime.datetime.strftime` for format codes):\n\n"
+      ]
+    },
+    {
+      "cell_type": "code",
+      "execution_count": null,
+      "metadata": {
+        "collapsed": false
+      },
+      "outputs": [],
+      "source": [
+        "fig, ax = plt.subplots(figsize=(5.4, 2), layout='constrained')\ntime = np.arange('1980-01-01', '1980-06-25', dtype='datetime64[D]')\nx = np.arange(len(time))\nax.plot(time, x)\nax.xaxis.set_major_locator(mdates.MonthLocator(bymonth=np.arange(1, 13, 2)))\nax.xaxis.set_major_formatter(mdates.DateFormatter('%b'))\nax.set_xlabel('1980')"
+      ]
+    },
+    {
+      "cell_type": "markdown",
+      "metadata": {},
+      "source": [
+        "The default locator is the `~.dates.AutoDateLocator`, and the default\nFormatter `~.dates.AutoDateFormatter`.  There are also  \"concise\" formatter\nand locators that give a more compact labelling, and can be set via rcParams.\nNote how instead of the redundant \"Jan\" label at the start of the year,\n\"1980\" is used instead.  See `date_concise_formatter` for more examples.\n\n"
+      ]
+    },
+    {
+      "cell_type": "code",
+      "execution_count": null,
+      "metadata": {
+        "collapsed": false
+      },
+      "outputs": [],
+      "source": [
+        "plt.rcParams['date.converter'] = 'concise'\n\nfig, ax = plt.subplots(figsize=(5.4, 2), layout='constrained')\ntime = np.arange('1980-01-01', '1980-06-25', dtype='datetime64[D]')\nx = np.arange(len(time))\nax.plot(time, x)"
+      ]
+    },
+    {
+      "cell_type": "markdown",
+      "metadata": {},
+      "source": [
+        "We can set the limits on the axis either by passing the appropriate dates as\nlimits, or by passing a floating-point value in the proper units of days\nsince the epoch.  If we need it, we can get this value from\n`~.dates.date2num`.\n\n"
+      ]
+    },
+    {
+      "cell_type": "code",
+      "execution_count": null,
+      "metadata": {
+        "collapsed": false
+      },
+      "outputs": [],
+      "source": [
+        "fig, axs = plt.subplots(2, 1, figsize=(5.4, 3), layout='constrained')\nfor ax in axs.flat:\n    time = np.arange('1980-01-01', '1980-06-25', dtype='datetime64[D]')\n    x = np.arange(len(time))\n    ax.plot(time, x)\n\n# set xlim using datetime64:\naxs[0].set_xlim(np.datetime64('1980-02-01'), np.datetime64('1980-04-01'))\n\n# set xlim using floats:\n# Note can get from mdates.date2num(np.datetime64('1980-02-01'))\naxs[1].set_xlim(3683, 3683+60)"
+      ]
+    },
+    {
+      "cell_type": "markdown",
+      "metadata": {},
+      "source": [
+        "## String conversion: categorical plots\n\nSometimes we want to label categories on an axis rather than numbers.\nMatplotlib allows this using a \"categorical\" converter (see\n`~.matplotlib.category`).\n\n"
+      ]
+    },
+    {
+      "cell_type": "code",
+      "execution_count": null,
+      "metadata": {
+        "collapsed": false
+      },
+      "outputs": [],
+      "source": [
+        "data = {'apple': 10, 'orange': 15, 'lemon': 5, 'lime': 20}\nnames = list(data.keys())\nvalues = list(data.values())\n\nfig, axs = plt.subplots(1, 3, figsize=(7, 3), sharey=True, layout='constrained')\naxs[0].bar(names, values)\naxs[1].scatter(names, values)\naxs[2].plot(names, values)\nfig.suptitle('Categorical Plotting')"
+      ]
+    },
+    {
+      "cell_type": "markdown",
+      "metadata": {},
+      "source": [
+        "Note that the \"categories\" are plotted in the order that they are first\nspecified and that subsequent plotting in a different order will not affect\nthe original order.  Further, new additions will be added on the end (see\n\"pear\" below):\n\n"
+      ]
+    },
+    {
+      "cell_type": "code",
+      "execution_count": null,
+      "metadata": {
+        "collapsed": false
+      },
+      "outputs": [],
+      "source": [
+        "fig, ax = plt.subplots(figsize=(5, 3), layout='constrained')\nax.bar(names, values)\n\n# plot in a different order:\nax.scatter(['lemon', 'apple'], [7, 12])\n\n# add a new category, \"pear\", and put the other categories in a different order:\nax.plot(['pear', 'orange', 'apple', 'lemon'], [13, 10, 7, 12], color='C1')"
+      ]
+    },
+    {
+      "cell_type": "markdown",
+      "metadata": {},
+      "source": [
+        "Note that when using ``plot`` like in the above, the order of the plotting is\nmapped onto the original order of the data, so the new line goes in the order\nspecified.\n\nThe category converter maps from categories to integers, starting at zero. So\ndata can also be manually added to the axis using a float.  Note that if a\nfloat is passed in that does not have a \"category\" associated with it, the\ndata point can still be plotted, but a tick will not be created.  In the\nfollowing, we plot data at 4.0 and 2.5, but no tick is added there because\nthose are not categories.\n\n"
+      ]
+    },
+    {
+      "cell_type": "code",
+      "execution_count": null,
+      "metadata": {
+        "collapsed": false
+      },
+      "outputs": [],
+      "source": [
+        "fig, ax = plt.subplots(figsize=(5, 3), layout='constrained')\nax.bar(names, values)\n# arguments for styling the labels below:\nargs = {'rotation': 70, 'color': 'C1',\n        'bbox': {'color': 'white', 'alpha': .7, 'boxstyle': 'round'}}\n\n\n# 0 gets labeled as \"apple\"\nax.plot(0, 2, 'd', color='C1')\nax.text(0, 3, 'Float x=0', **args)\n\n# 2 gets labeled as \"lemon\"\nax.plot(2, 2, 'd', color='C1')\nax.text(2, 3, 'Float x=2', **args)\n\n# 4 doesn't get a label\nax.plot(4, 2, 'd', color='C1')\nax.text(4, 3, 'Float x=4', **args)\n\n# 2.5 doesn't get a label\nax.plot(2.5, 2, 'd', color='C1')\nax.text(2.5, 3, 'Float x=2.5', **args)"
+      ]
+    },
+    {
+      "cell_type": "markdown",
+      "metadata": {},
+      "source": [
+        "Setting the limits for a category axis can be done by specifying the\ncategories, or by specifying floating point numbers:\n\n"
+      ]
+    },
+    {
+      "cell_type": "code",
+      "execution_count": null,
+      "metadata": {
+        "collapsed": false
+      },
+      "outputs": [],
+      "source": [
+        "fig, axs = plt.subplots(2, 1, figsize=(5, 5), layout='constrained')\nax = axs[0]\nax.bar(names, values)\nax.set_xlim('orange', 'lemon')\nax.set_xlabel('limits set with categories')\nax = axs[1]\nax.bar(names, values)\nax.set_xlim(0.5, 2.5)\nax.set_xlabel('limits set with floats')"
+      ]
+    },
+    {
+      "cell_type": "markdown",
+      "metadata": {},
+      "source": [
+        "The category axes are helpful for some plot types, but can lead to confusion\nif data is read in as a list of strings, even if it is meant to be a list of\nfloats or dates.  This sometimes happens when reading comma-separated value\n(CSV) files. The categorical locator and formatter will put a tick at every\nstring value and label each one as well:\n\n"
+      ]
+    },
+    {
+      "cell_type": "code",
+      "execution_count": null,
+      "metadata": {
+        "collapsed": false
+      },
+      "outputs": [],
+      "source": [
+        "fig, ax = plt.subplots(figsize=(5.4, 2.5), layout='constrained')\nx = [str(xx) for xx in np.arange(100)]  # list of strings\nax.plot(x, np.arange(100))\nax.set_xlabel('x is list of strings')"
+      ]
+    },
+    {
+      "cell_type": "markdown",
+      "metadata": {},
+      "source": [
+        "If this is not desired, then simply convert the data to floats before plotting:\n\n"
+      ]
+    },
+    {
+      "cell_type": "code",
+      "execution_count": null,
+      "metadata": {
+        "collapsed": false
+      },
+      "outputs": [],
+      "source": [
+        "fig, ax = plt.subplots(figsize=(5.4, 2.5), layout='constrained')\nx = np.asarray(x, dtype='float')  # array of float.\nax.plot(x, np.arange(100))\nax.set_xlabel('x is array of floats')"
+      ]
+    },
+    {
+      "cell_type": "markdown",
+      "metadata": {},
+      "source": [
+        "## Determine converter, formatter, and locator on an axis\n\nSometimes it is helpful to be able to debug what Matplotlib is using to\nconvert the incoming data.  We can do that by querying the ``converter``\nproperty on the axis.  We can also query the formatters and locators using\n`~.axis.Axis.get_major_locator` and `~.axis.Axis.get_major_formatter`.\n\nNote that by default the converter is *None*.\n\n"
+      ]
+    },
+    {
+      "cell_type": "code",
+      "execution_count": null,
+      "metadata": {
+        "collapsed": false
+      },
+      "outputs": [],
+      "source": [
+        "fig, axs = plt.subplots(3, 1, figsize=(6.4, 7), layout='constrained')\nx = np.arange(100)\nax = axs[0]\nax.plot(x, x)\nlabel = f'Converter: {ax.xaxis.converter}\\n '\nlabel += f'Locator: {ax.xaxis.get_major_locator()}\\n'\nlabel += f'Formatter: {ax.xaxis.get_major_formatter()}\\n'\nax.set_xlabel(label)\n\nax = axs[1]\ntime = np.arange('1980-01-01', '1980-06-25', dtype='datetime64[D]')\nx = np.arange(len(time))\nax.plot(time, x)\nlabel = f'Converter: {ax.xaxis.converter}\\n '\nlabel += f'Locator: {ax.xaxis.get_major_locator()}\\n'\nlabel += f'Formatter: {ax.xaxis.get_major_formatter()}\\n'\nax.set_xlabel(label)\n\nax = axs[2]\ndata = {'apple': 10, 'orange': 15, 'lemon': 5, 'lime': 20}\nnames = list(data.keys())\nvalues = list(data.values())\nax.plot(names, values)\nlabel = f'Converter: {ax.xaxis.converter}\\n '\nlabel += f'Locator: {ax.xaxis.get_major_locator()}\\n'\nlabel += f'Formatter: {ax.xaxis.get_major_formatter()}\\n'\nax.set_xlabel(label)"
+      ]
+    },
+    {
+      "cell_type": "markdown",
+      "metadata": {},
+      "source": [
+        "## More about \"unit\" support\n\nThe support for dates and categories is part of \"units\" support that is built\ninto Matplotlib.  This is described at `.matplotlib.units` and in the\n`basic_units` example.\n\nUnit support works by querying the type of data passed to the plotting\nfunction and dispatching to the first converter in a list that accepts that\ntype of data.  So below, if ``x`` has ``datetime`` objects in it, the\nconverter will be ``_SwitchableDateConverter``; if it has has strings in it,\nit will be sent to the ``StrCategoryConverter``.\n\n"
+      ]
+    },
+    {
+      "cell_type": "code",
+      "execution_count": null,
+      "metadata": {
+        "collapsed": false
+      },
+      "outputs": [],
+      "source": [
+        "for k, v in munits.registry.items():\n    print(f\"type: {k};\\n    converter: {type(v)}\")"
+      ]
+    },
+    {
+      "cell_type": "markdown",
+      "metadata": {},
+      "source": [
+        "There are a number of downstream libraries that provide their own converters\nwith locators and formatters.  Physical unit support is provided by\n[astropy](https://www.astropy.org), [pint](https://pint.readthedocs.io), and\n[unyt](https://unyt.readthedocs.io), among others.\n\nHigh level libraries like [pandas](https://pandas.pydata.org) and\n[nc-time-axis](https://nc-time-axis.readthedocs.io) (and thus\n[xarray](https://docs.xarray.dev)) provide their own datetime support.\nThis support can sometimes be incompatible with Matplotlib native datetime\nsupport, so care should be taken when using Matplotlib locators and\nformatters if these libraries are being used.\n\n"
+      ]
+    }
+  ],
+  "metadata": {
+    "kernelspec": {
+      "display_name": "Python 3",
+      "language": "python",
+      "name": "python3"
+    },
+    "language_info": {
+      "codemirror_mode": {
+        "name": "ipython",
+        "version": 3
+      },
+      "file_extension": ".py",
+      "mimetype": "text/x-python",
+      "name": "python",
+      "nbconvert_exporter": "python",
+      "pygments_lexer": "ipython3",
+      "version": "3.9.18"
+    }
+  },
+  "nbformat": 4,
+  "nbformat_minor": 0
+}

_downloads/008c73d5ac1c4af82c0b90fde922ebb9/stairs.py

@@ -0,0 +1,24 @@
+"""
+==============
+stairs(values)
+==============
+
+See `~matplotlib.axes.Axes.stairs`.
+"""
+import matplotlib.pyplot as plt
+import numpy as np
+
+plt.style.use('_mpl-gallery')
+
+# make data
+y = [4.8, 5.5, 3.5, 4.6, 6.5, 6.6, 2.6, 3.0]
+
+# plot
+fig, ax = plt.subplots()
+
+ax.stairs(y, linewidth=2.5)
+
+ax.set(xlim=(0, 8), xticks=np.arange(1, 8),
+       ylim=(0, 8), yticks=np.arange(1, 8))
+
+plt.show()

_downloads/00aacc25eb4ed2eaffa3c821d5562b6d/whats_new_3-6-0-5.py

@@ -0,0 +1,7 @@
+x = np.linspace(1., 3., 10)
+y = x**3
+
+fig, ax = plt.subplots()
+ax.plot(x, y, linestyle='--', color='orange', gapcolor='blue',
+        linewidth=3, label='a striped line')
+ax.legend()