python数据分析——手动绘制散点图的背景颜色实例

import numpy as np
import pandas as pd
from pandas import Series,DataFrame
import matplotlib.pyplot as plt

 

手动绘制散点图的背景颜色

In [11]:

x = [1,2,3]
y = [6,7,8]
plt.scatter(x,y)

Out[11]:

<matplotlib.collections.PathCollection at 0x1f8d3a63c50>

 

 

• 设定一组x，y

In [12]:

x = np.linspace(1,3,num=100)
y = np.linspace(6,8,num=100)

In [14]:

# 返回一个网格矩阵
xx,yy = np.meshgrid(x,y)

In [15]:

xx.shape

Out[15]:

(100, 100)

In [18]:

# 生成两列坐标点
xy = np.c_[xx.reshape(10000,),yy.reshape(10000,)]
xy

Out[18]:

array([[1.        , 6.        ],
       [1.02020202, 6.        ],
       [1.04040404, 6.        ],
       ...,
       [2.95959596, 8.        ],
       [2.97979798, 8.        ],
       [3.        , 8.        ]])

In [19]:

# 取第一列
xy[:,0]

Out[19]:

array([1.        , 1.02020202, 1.04040404, ..., 2.95959596, 2.97979798,
       3.        ])

In [21]:

# xy中第一列为scatter中第一个参数，第二列为scatter中第二个参数
plt.scatter(xy[:,0],xy[:,1])
plt.scatter([1,2,3],[6,7,8])

Out[21]:

<matplotlib.collections.PathCollection at 0x1f8d3601fd0>

 

 

meshgrid举例

a = np.array([1,2,3])

b = np.array([4,5,6])

In [8]:

aa,bb = np.meshgrid(a,b)

In [9]:

display(aa,bb)

array([[1, 2, 3],
       [1, 2, 3],
       [1, 2, 3]])

array([[4, 4, 4],
       [5, 5, 5],
       [6, 6, 6]])

In [12]:

display(aa.reshape(9,),bb.reshape(9,))

array([1, 2, 3, 1, 2, 3, 1, 2, 3])

array([4, 4, 4, 5, 5, 5, 6, 6, 6])

In [13] 

A,B = aa.reshape(9,),bb.reshape(9,)

In [14]:

np.c_[A,B]

Out[14]:

array([[1, 4],
       [2, 4],
       [3, 4],
       [1, 5],
       [2, 5],
       [3, 5],
       [1, 6],
       [2, 6],
       [3, 6]])