Plots画线

import numpy as np

linear_data = np.array([1,2,3,4,5,6,7,8])
exponential_data = linear_data**2

plt.figure()
#画直线和平方后的线
plt.plot(linear_data, '-o', exponential_data, '-o')

#用红色虚线画另一组点
plt.plot([22,44,55], '--r')
#添加横纵坐标标注和图的标题
plt.xlabel('Some data')
plt.ylabel('Some other data')
plt.title('A title')
#用图例项添加图例，因为之前没有给线段定义labels
plt.legend(['Baseline', 'Competition', 'Us'])

#填充一次和两次线段之间的空间
plt.gca().fill_between(range(len(linear_data)), 
                       linear_data, exponential_data, 
                       facecolor='blue', 
                       alpha=0.25)

import pandas as pd

plt.figure()
observation_dates = np.arange('2017-01-01', '2017-01-09', dtype='datetime64[D]')
observation_dates = map(pd.to_datetime, observation_dates) # trying to plot a map will result in an error
plt.plot(observation_dates, linear_data, '-o',  observation_dates, exponential_data, '-o')

错误代码

TypeError: object of type 'map' has no len()

 

plt.figure()
observation_dates = np.arange('2017-01-01', '2017-01-09', dtype='datetime64[D]')
observation_dates = list(map(pd.to_datetime, observation_dates)) # 把map转换成list来避免错误
plt.plot(observation_dates, linear_data, '-o',  observation_dates, exponential_data, '-o')

x = plt.gca().xaxis

# 因为日期太长导致横坐标相互遮盖，所以旋转横坐标值45°
for item in x.get_ticklabels():
    item.set_rotation(45)

# 调整坐标系防止横坐标旋转部分被遮盖
plt.subplots_adjust(bottom=0.25)
#添加横纵坐标标注和图标标题
ax = plt.gca()
ax.set_xlabel('Date')
ax.set_ylabel('Units')
ax.set_title('Exponential vs. Linear performance')

#在文本用添加数学表达式
ax.set_title("Exponential ($x^2$) vs. Linear ($x$) performance")