使用滑块matplotlib更改不透明度

Question

我一直在玩matplotlib，因为我正在学习它。所以我创建了一个带有一些值的字典，并尝试了不同的东西。目前我对滑块和不透明度有点困惑。在我的代码中，除了滑块之外，实际上存在几个问题。但这个问题是关于滑块的。

第一个错误：必须有三个滑块 - ＆gt;有一个 第二个错误：不透明度不会更新。

你能解释一下（我的意思是代码有什么问题）是错误并帮助修复它们吗？

import matplotlib.pyplot as plt
from matplotlib.widgets import CheckButtons
import numpy as np
from matplotlib.pyplot import cm
from numpy.random import random
from matplotlib.widgets import Slider

dictFruit = {'apple' : [list(random(2)), list(random(2)), list(random(2))], 'pear' : [list(random(2)), list(random(2)), list(random(2))], 'cherry' : [list(random(2)), list(random(2)), list(random(2))]}
color=iter(cm.rainbow(np.linspace(0,1,len(dictFruit))))
allKeys = dictFruit.keys()
print('ALL MY KEYS', allKeys)
allItems = {}

opacityFruit = 0

fig = plt.figure(1)
ax = fig.add_subplot(111)

#NON-PLOT ELEMENTS

rax = plt.axes([0.15, 0.4, 0.1, 0.15])
sliderBox = plt.axes([0.15, 0.025, 0.65, 0.03])

### SLIDERS
def update(val):
    opacity = opacitySlide.val
    print('NEW OPACITY VALUE', opacity)
    plt.draw()
    return opacity

for item in allKeys:
    opacitySlide = Slider(sliderBox, 'Opacity', 0.0, 1.0, valinit=1.0)
    opacitySlide.on_changed(update)
op = update(0.5)

colorDictAll = {}

for fruit in dictFruit:
    c=next(color)
    colorDictAll[fruit] = c
    print(dictFruit[fruit])
    xAll = []
    yAll = []
    for idx, item in enumerate(dictFruit[fruit]):
        x = item[0]
        y = item[1]
        xAll.append(x)
        yAll.append(y)
    curIt = ax.scatter(xAll, yAll, c = c, label = fruit, s = 100.0, alpha=update(1))
    print(curIt)
    allItems[fruit] = curIt
    print(allItems)
print('CURRENT ITEMS')
print(allItems)

#CHECK BUTTONS

check = CheckButtons(rax, ('apple', 'pear', 'cherry'), (True, True, True))
def func(label):
    for fruit in allKeys:
        if label == fruit:
            allItems[fruit].set_visible(not allItems[fruit].get_visible())
    plt.draw()
for rec in check.rectangles:
    idx = check.rectangles.index(rec)
    print(idx)
    print('REC', rec)
    currentFruit = allKeys[idx]
    currentFruitColor = colorDictAll[currentFruit]
    rec.set_facecolor(currentFruitColor)
check.on_clicked(func)
plt.legend()
plt.show()