matplotlib绘图库
Python库记录系列.
安装
pip install matplotlib
# 会自动安装依赖numpy
基本使用
常用格式
plt.plot(range(10), linestyle='--', marker='o', color='b')
# 等价于
plt.plot(range(10), '--bo')
基本概念
- Label/标签:标明指定数据类型或分组
- Annotation/标注:对数据的补充说明信息
- Legend/图例:数据列表的分类说明(以颜色等区分)
import matplotlib.pyplot as plt
import numpy as np
#
plt.ylabel("Values")
#
plt.annotate(xy=[1,1], s="First Entry")
plt.annotate(label, # this is the text
(x,y), # this is the point to label
textcoords="offset points", # how to position the text
xytext=(0,10), # distance from text to points (x,y)
ha='center') # horizontal alignment can be left, right or center
# Legend
plt.legend(['First', 'Second'], loc=4)
t2 = np.arange(0.0, 2.0, 0.01)
fig, ax = plt.subplots()
# 注意,的使用,l1是个Line2D实例
l1, = ax.plot(t2, np.exp(-t2))
ax.legend((l1), ('exp'), loc='upper right', shadow=True)
# 添加文本/text
# 默认左对齐
plt.text(8,3,'This text ends at point (8,3)',horizontalalignment='right')
常用功能
支持中文标签
import matplotlib.pyplot as plt
# 用来正常显示中文标签
plt.rcParams['font.sans-serif'] = ['SimHei']
# 用来正常显示负号
plt.rcParams['axes.unicode_minus'] = False
numpy
import numpy as np
# 范围取值
np.arange(20, 120, 20)
# 读取csv文件
data = np.genfromtxt('result.csv', delimiter=',', skip_header=True)
# 交换二维数组
data1 = np.swapaxes(data, 0, 1)
# 交换方式二
x = np.arange(4).reshape((2,2))
# 转换/对调
np.transpose(x)
扩展阅读
numpy