I am using matplotlib to make scatter plots. Each point on the scatter plot is associated with a named object. I would like to be able to see the name of an object when I hover my cursor over the point on the scatter plot associated with that object. In particular, it would be nice to be able to quickly see the names of the points that are outliers. The closest thing I have been able to find while searching here is the annotate command, but that appears to create a fixed label on the plot. Unfortunately, with the number of points that I have, the scatter plot would be unreadable if I labeled each point. Does anyone know of a way to create labels that only appear when the cursor hovers in the vicinity of that point?


当前回答

在matplotlib状态栏中显示对象信息

特性

不需要额外的库 干净的情节 没有厂牌和艺人的重叠 支持多艺术家标签 可以处理来自不同绘图调用的艺术家(如scatter, plot, add_patch) 库风格的代码

Code

### imports
import matplotlib as mpl
import matplotlib.pylab as plt
import numpy as np


# https://stackoverflow.com/a/47166787/7128154
# https://matplotlib.org/3.3.3/api/collections_api.html#matplotlib.collections.PathCollection
# https://matplotlib.org/3.3.3/api/path_api.html#matplotlib.path.Path
# https://stackoverflow.com/questions/15876011/add-information-to-matplotlib-navigation-toolbar-status-bar
# https://stackoverflow.com/questions/36730261/matplotlib-path-contains-point
# https://stackoverflow.com/a/36335048/7128154
class StatusbarHoverManager:
    """
    Manage hover information for mpl.axes.Axes object based on appearing
    artists.

    Attributes
    ----------
    ax : mpl.axes.Axes
        subplot to show status information
    artists : list of mpl.artist.Artist
        elements on the subplot, which react to mouse over
    labels : list (list of strings) or strings
        each element on the top level corresponds to an artist.
        if the artist has items
        (i.e. second return value of contains() has key 'ind'),
        the element has to be of type list.
        otherwise the element if of type string
    cid : to reconnect motion_notify_event
    """
    def __init__(self, ax):
        assert isinstance(ax, mpl.axes.Axes)


        def hover(event):
            if event.inaxes != ax:
                return
            info = 'x={:.2f}, y={:.2f}'.format(event.xdata, event.ydata)
            ax.format_coord = lambda x, y: info
        cid = ax.figure.canvas.mpl_connect("motion_notify_event", hover)

        self.ax = ax
        self.cid = cid
        self.artists = []
        self.labels = []

    def add_artist_labels(self, artist, label):
        if isinstance(artist, list):
            assert len(artist) == 1
            artist = artist[0]

        self.artists += [artist]
        self.labels += [label]

        def hover(event):
            if event.inaxes != self.ax:
                return
            info = 'x={:.2f}, y={:.2f}'.format(event.xdata, event.ydata)
            for aa, artist in enumerate(self.artists):
                cont, dct = artist.contains(event)
                if not cont:
                    continue
                inds = dct.get('ind')
                if inds is not None:  # artist contains items
                    for ii in inds:
                        lbl = self.labels[aa][ii]
                        info += ';   artist [{:d}, {:d}]: {:}'.format(
                            aa, ii, lbl)
                else:
                    lbl = self.labels[aa]
                    info += ';   artist [{:d}]: {:}'.format(aa, lbl)
            self.ax.format_coord = lambda x, y: info

        self.ax.figure.canvas.mpl_disconnect(self.cid)
        self.cid = self.ax.figure.canvas.mpl_connect(
            "motion_notify_event", hover)



def demo_StatusbarHoverManager():
    fig, ax = plt.subplots()
    shm = StatusbarHoverManager(ax)

    poly = mpl.patches.Polygon(
        [[0,0], [3, 5], [5, 4], [6,1]], closed=True, color='green', zorder=0)
    artist = ax.add_patch(poly)
    shm.add_artist_labels(artist, 'polygon')

    artist = ax.scatter([2.5, 1, 2, 3], [6, 1, 1, 7], c='blue', s=10**2)
    lbls = ['point ' + str(ii) for ii in range(4)]
    shm.add_artist_labels(artist, lbls)

    artist = ax.plot(
        [0, 0, 1, 5, 3], [0, 1, 1, 0, 2], marker='o', color='red')
    lbls = ['segment ' + str(ii) for ii in range(5)]
    shm.add_artist_labels(artist, lbls)

    plt.show()


# --- main
if __name__== "__main__":
    demo_StatusbarHoverManager()

其他回答

对http://matplotlib.org/users/shell.html:中提供的示例进行了轻微编辑

import numpy as np
import matplotlib.pyplot as plt

fig = plt.figure()
ax = fig.add_subplot(111)
ax.set_title('click on points')

line, = ax.plot(np.random.rand(100), '-', picker=5)  # 5 points tolerance


def onpick(event):
    thisline = event.artist
    xdata = thisline.get_xdata()
    ydata = thisline.get_ydata()
    ind = event.ind
    print('onpick points:', *zip(xdata[ind], ydata[ind]))


fig.canvas.mpl_connect('pick_event', onpick)

plt.show()

就像Sohaib问的,这是一条直线

我做了一个多行注释系统,添加到:https://stackoverflow.com/a/47166787/10302020。 最新版本: https://github.com/AidenBurgess/MultiAnnotationLineGraph

只需更改底部部分中的数据。

import matplotlib.pyplot as plt


def update_annot(ind, line, annot, ydata):
    x, y = line.get_data()
    annot.xy = (x[ind["ind"][0]], y[ind["ind"][0]])
    # Get x and y values, then format them to be displayed
    x_values = " ".join(list(map(str, ind["ind"])))
    y_values = " ".join(str(ydata[n]) for n in ind["ind"])
    text = "{}, {}".format(x_values, y_values)
    annot.set_text(text)
    annot.get_bbox_patch().set_alpha(0.4)


def hover(event, line_info):
    line, annot, ydata = line_info
    vis = annot.get_visible()
    if event.inaxes == ax:
        # Draw annotations if cursor in right position
        cont, ind = line.contains(event)
        if cont:
            update_annot(ind, line, annot, ydata)
            annot.set_visible(True)
            fig.canvas.draw_idle()
        else:
            # Don't draw annotations
            if vis:
                annot.set_visible(False)
                fig.canvas.draw_idle()


def plot_line(x, y):
    line, = plt.plot(x, y, marker="o")
    # Annotation style may be changed here
    annot = ax.annotate("", xy=(0, 0), xytext=(-20, 20), textcoords="offset points",
                        bbox=dict(boxstyle="round", fc="w"),
                        arrowprops=dict(arrowstyle="->"))
    annot.set_visible(False)
    line_info = [line, annot, y]
    fig.canvas.mpl_connect("motion_notify_event",
                           lambda event: hover(event, line_info))


# Your data values to plot
x1 = range(21)
y1 = range(0, 21)
x2 = range(21)
y2 = range(0, 42, 2)
# Plot line graphs
fig, ax = plt.subplots()
plot_line(x1, y1)
plot_line(x2, y2)
plt.show()

Mplcursors对我很有用。Mplcursors为matplotlib提供了可单击的注释。它很大程度上受到mpldatacursor (https://github.com/joferkington/mpldatacursor)的启发,具有非常简化的API

import matplotlib.pyplot as plt
import numpy as np
import mplcursors

data = np.outer(range(10), range(1, 5))

fig, ax = plt.subplots()
lines = ax.plot(data)
ax.set_title("Click somewhere on a line.\nRight-click to deselect.\n"
             "Annotations can be dragged.")

mplcursors.cursor(lines) # or just mplcursors.cursor()

plt.show()

在matplotlib状态栏中显示对象信息

特性

不需要额外的库 干净的情节 没有厂牌和艺人的重叠 支持多艺术家标签 可以处理来自不同绘图调用的艺术家(如scatter, plot, add_patch) 库风格的代码

Code

### imports
import matplotlib as mpl
import matplotlib.pylab as plt
import numpy as np


# https://stackoverflow.com/a/47166787/7128154
# https://matplotlib.org/3.3.3/api/collections_api.html#matplotlib.collections.PathCollection
# https://matplotlib.org/3.3.3/api/path_api.html#matplotlib.path.Path
# https://stackoverflow.com/questions/15876011/add-information-to-matplotlib-navigation-toolbar-status-bar
# https://stackoverflow.com/questions/36730261/matplotlib-path-contains-point
# https://stackoverflow.com/a/36335048/7128154
class StatusbarHoverManager:
    """
    Manage hover information for mpl.axes.Axes object based on appearing
    artists.

    Attributes
    ----------
    ax : mpl.axes.Axes
        subplot to show status information
    artists : list of mpl.artist.Artist
        elements on the subplot, which react to mouse over
    labels : list (list of strings) or strings
        each element on the top level corresponds to an artist.
        if the artist has items
        (i.e. second return value of contains() has key 'ind'),
        the element has to be of type list.
        otherwise the element if of type string
    cid : to reconnect motion_notify_event
    """
    def __init__(self, ax):
        assert isinstance(ax, mpl.axes.Axes)


        def hover(event):
            if event.inaxes != ax:
                return
            info = 'x={:.2f}, y={:.2f}'.format(event.xdata, event.ydata)
            ax.format_coord = lambda x, y: info
        cid = ax.figure.canvas.mpl_connect("motion_notify_event", hover)

        self.ax = ax
        self.cid = cid
        self.artists = []
        self.labels = []

    def add_artist_labels(self, artist, label):
        if isinstance(artist, list):
            assert len(artist) == 1
            artist = artist[0]

        self.artists += [artist]
        self.labels += [label]

        def hover(event):
            if event.inaxes != self.ax:
                return
            info = 'x={:.2f}, y={:.2f}'.format(event.xdata, event.ydata)
            for aa, artist in enumerate(self.artists):
                cont, dct = artist.contains(event)
                if not cont:
                    continue
                inds = dct.get('ind')
                if inds is not None:  # artist contains items
                    for ii in inds:
                        lbl = self.labels[aa][ii]
                        info += ';   artist [{:d}, {:d}]: {:}'.format(
                            aa, ii, lbl)
                else:
                    lbl = self.labels[aa]
                    info += ';   artist [{:d}]: {:}'.format(aa, lbl)
            self.ax.format_coord = lambda x, y: info

        self.ax.figure.canvas.mpl_disconnect(self.cid)
        self.cid = self.ax.figure.canvas.mpl_connect(
            "motion_notify_event", hover)



def demo_StatusbarHoverManager():
    fig, ax = plt.subplots()
    shm = StatusbarHoverManager(ax)

    poly = mpl.patches.Polygon(
        [[0,0], [3, 5], [5, 4], [6,1]], closed=True, color='green', zorder=0)
    artist = ax.add_patch(poly)
    shm.add_artist_labels(artist, 'polygon')

    artist = ax.scatter([2.5, 1, 2, 3], [6, 1, 1, 7], c='blue', s=10**2)
    lbls = ['point ' + str(ii) for ii in range(4)]
    shm.add_artist_labels(artist, lbls)

    artist = ax.plot(
        [0, 0, 1, 5, 3], [0, 1, 1, 0, 2], marker='o', color='red')
    lbls = ['segment ' + str(ii) for ii in range(5)]
    shm.add_artist_labels(artist, lbls)

    plt.show()


# --- main
if __name__== "__main__":
    demo_StatusbarHoverManager()

Mpld3为我解决它。 编辑(新增代码):

import matplotlib.pyplot as plt
import numpy as np
import mpld3

fig, ax = plt.subplots(subplot_kw=dict(axisbg='#EEEEEE'))
N = 100

scatter = ax.scatter(np.random.normal(size=N),
                 np.random.normal(size=N),
                 c=np.random.random(size=N),
                 s=1000 * np.random.random(size=N),
                 alpha=0.3,
                 cmap=plt.cm.jet)
ax.grid(color='white', linestyle='solid')

ax.set_title("Scatter Plot (with tooltips!)", size=20)

labels = ['point {0}'.format(i + 1) for i in range(N)]
tooltip = mpld3.plugins.PointLabelTooltip(scatter, labels=labels)
mpld3.plugins.connect(fig, tooltip)

mpld3.show()

你可以检查这个例子