Python Matplotlib条形图，具有不同颜色的条形图和显示值的条形图

我想改变这段代码中条的颜色，所有条都是相同的颜色，我想在每个条的顶部显示不同的值，这些值存储在maxteet，p，n变量中

x=[]
x.append(max_tweets)
x.append(p)
x.append(n)
label=('tweets','positivity','nagitivity')
label_pos=np.arange(len(label))
plt.bar(label_pos,x,align='center',color='k')
plt.xticks(label_pos,label)
plt.xlabel('People Behaviour and Emotions')
plt.title('Sentiment Analysis')
plt.show()

输出：

import matplotlib.pylab as plt
import numpy as np
max_tweets = 19
p = 20
n = 30

datas = [{'label':'tweets', 'color': 'r', 'height': max_tweets},
    {'label':'positivity', 'color': 'g', 'height': p},
    {'label':'nagitivity', 'color': 'b', 'height': n}]

i = 0
for data in datas:
    plt.bar(i, data['height'],align='center',color=data['color'])
    i += 1

labels = [data['label'] for data in datas]
pos = [i for i in range(len(datas)) ]
plt.xticks(pos, labels)
plt.xlabel('People Behaviour and Emotions')
plt.title('Sentiment Analysis')
plt.show()