scatter(x, y, s=None, c=None, marker=None, cmap=None, norm=None, vmin=None, vmax=None, alpha=None, linewidths=None, verts=None, edgecolors=None, hold=None, data=None, **kwargs)
参数(Parameters)说明：
x，y：array_like，shape（n，）
输入数据
s：标量或array_like，shape（n，），可选
大小以点数^ 2。默认是`rcParams ['lines.markersize'] ** 2`。
c：颜色，顺序或颜色顺序，可选，默认：'b'
`c`可以是单个颜色格式的字符串，也可以是一系列颜色
规范的长度为`N`，或一系列`N`数字
使用通过kwargs指定的`cmap`和`norm`映射到颜色
（见下文）。请注意，`c`不应该是单个数字RGB或
RGBA序列，因为这与数组无法区分
值将被彩色映射。 `c`可以是一个二维数组，其中的
行是RGB或RGBA，但是，包括单个的情况
行为所有点指定相同的颜色。
marker：`〜matplotlib.markers.MarkerStyle`，可选，默认值：'o'
请参阅`〜matplotlib.markers`以获取有关不同的更多信息
标记分散支持的样式。 `marker`可以是
该类的实例或特定文本的简写
标记。
cmap：`〜matplotlib.colors.Colormap`，可选，默认：无
一个`〜matplotlib.colors.Colormap`实例或注册名称。
`cmap`仅在`c`是浮点数组时使用。如果没有，
默认为rc`image.cmap`。
norm：`〜matplotlib.colors.Normalize`，可选，默认：无
`〜matplotlib.colors.Normalize`实例用于缩放
亮度数据为0,1。`norm`只有在`c`是一个数组时才被使用
彩车。如果`None'，则使用默认值：func：`normalize`。
vmin，vmax：标量，可选，默认值：无
`vmin`和`vmax`与`norm`结合使用来标准化
亮度数据。如果其中任何一个都是`无'，那么最小和最大的
使用颜色数组。请注意，如果你通过一个“规范”实例，你的
`vmin`和`vmax`的设置将被忽略。
alpha：标量，可选，默认值：无
alpha混合值，介于0（透明）和1（不透明）之间，
linewidths：标量或array_like，可选，默认值：无
如果无，则默认为（lines.linewidth，）。
verts：（x，y）的序列，可选
如果`marker`为None，这些顶点将用于
构建标记。标记的中心位于
在（0,0）为标准化单位。整体标记重新调整
由``s``完成。
edgecolors ：颜色或颜色顺序，可选，默认值：无
如果无，则默认为'face'
如果'face'，边缘颜色将永远是相同的
脸色。
如果它是'none'，补丁边界不会
被画下来。
对于未填充的标记，“edgecolors”kwarg
被忽视并被迫在内部“面对”。
简单点绘制
- 按到原点的距离增大点的大小
x = [0,2,4,6,8,10]
y = [0]*len(x)
s = [20*4**n for n in range(len(x))]
plt.scatter(x,y,s=s)
plt.show()
image.png
x = [0,2,4,6,8,10]
y = [0]*len(x)
s = [20*2**n for n in range(len(x))]
plt.scatter(x,y,s=s)
plt.show()
image.png
import numpy as np
import matplotlib.pyplot as plt
fig=plt.figure(figsize=(8,6))
#Generating a Gaussion dataset:
#creating random vectors from the multivariate normal distribution
#given mean and covariance
mu_vec1=np.array([0,0])
cov_mat1=np.array([[1,0],[0,1]])
X=np.random.multivariate_normal(mu_vec1,cov_mat1,500)
R=X**2
R_sum=R.sum(axis=1)
plt.scatter(X[:,0],X[:,1],color='green',marker='o',
s=32.*R_sum,edgecolor='black',alpha=0.5)
plt.show()
image.png
- 散点绘制
from matplotlib import pyplot as plt
import numpy as np
# Generating a Gaussion dTset:
#Creating random vectors from the multivaritate normal distribution
#givem mean and covariance
mu_vecl = np.array([0, 0])
cov_matl = np.array([[2,0],[0,2]])
x1_samples = np.random.multivariate_normal(mu_vecl, cov_matl,100)
x2_samples = np.random.multivariate_normal(mu_vecl+0.2, cov_matl +0.2, 100)
x3_samples = np.random.multivariate_normal(mu_vecl+0.4, cov_matl +0.4, 100)
plt.figure(figsize = (8, 6))
plt.scatter(x1_samples[:,0], x1_samples[:, 1], marker='x',
color = 'blue', alpha=0.7, label = 'x1 samples')
plt.scatter(x2_samples[:,0], x1_samples[:,1], marker='o',
color ='green', alpha=0.7, label = 'x2 samples')
plt.scatter(x3_samples[:,0], x1_samples[:,1], marker='^',
color ='red', alpha=0.7, label = 'x3 samples')
plt.title('Basic scatter plot')
plt.ylabel('variable X')
plt.xlabel('Variable Y')
plt.legend(loc = 'upper right')
plt.show()
import matplotlib.pyplot as plt
fig,ax = plt.subplots()
ax.plot([0],[0], marker="o", markersize=10)
ax.plot([0.07,0.93],[0,0], linewidth=10)
ax.scatter([1],[0], s=100)
ax.plot([0],[1], marker="o", markersize=22)
ax.plot([0.14,0.86],[1,1], linewidth=22)
ax.scatter([1],[1], s=22**2)
plt.show()
import matplotlib.pyplot as plt
for dpi in [72,100,144]:
fig,ax = plt.subplots(figsize=(1.5,2), dpi=dpi)
ax.set_title("fig.dpi={}".format(dpi))
ax.set_ylim(-3,3)
ax.set_xlim(-2,2)
ax.scatter([0],[1], s=10**2,
marker="s", linewidth=0, label="100 points^2")
ax.scatter([1],[1], s=(10*72./fig.dpi)**2,
marker="s", linewidth=0, label="100 pixels^2")
ax.legend(loc=8,framealpha=1, fontsize=8)
fig.savefig("fig{}.png".format(dpi), bbox_inches="tight")
plt.show()
image.png
import matplotlib.pyplot as plt
for dpi in [72,100,144]:
fig,ax = plt.subplots(figsize=(1.5,2), dpi=dpi)
ax.set_title("fig.dpi={}".format(dpi))
ax.set_ylim(-3,3)
ax.set_xlim(-2,2)
ax.scatter([0],[1], s=10**2,
marker="s", linewidth=0, label="100 points^2")
ax.scatter([1],[1], s=(10*72./fig.dpi)**2,
marker="s", linewidth=0, label="100 pixels^2")
ax.legend(loc=8,framealpha=1, fontsize=8)
fig.savefig("fig{}.png".format(dpi), bbox_inches="tight")
plt.show()
image.png
import numpy as np
import matplotlib.pyplot as plt
x1 = np.random.randn(20)
x2 = np.random.randn(20)
plt.figure(1)
# you can specify the marker size two ways directly:
plt.plot(x1, 'bo', markersize=20) # blue circle with size 10
plt.plot(x2, 'ro', ms=10,) # ms is just an alias for markersize
plt.show()
image.png
plt.scatter(2, 1, s=4000, c='r')
plt.scatter(2, 1, s=1000 ,c='b')
plt.scatter(2, 1, s=10, c='g')
image.png
- 带标签点绘制
import matplotlib.pyplot as plt
x_coords = [0.13, 0.22, 0.39, 0.59, 0.68, 0.74,0.93]
y_coords = [0.75, 0.34, 0.44, 0.52, 0.80, 0.25,0.55]
fig = plt.figure(figsize = (8,5))
plt.scatter(x_coords, y_coords, marker = 's', s = 50)
for x, y in zip(x_coords, y_coords):
plt.annotate('(%s,%s)'%(x,y), xy=(x,y),xytext = (0, -10), textcoords = 'offset points',ha = 'center', va = 'top')
plt.xlim([0,1])
plt.ylim([0,1])
plt.show()
image.png
- 用曲线把样本分成两类
# 2-category classfication with random 2D-sample data
# from a multivariate normal distribution
import numpy as np
from matplotlib import pyplot as plt
def decision_boundary(x_1):
"""Calculates the x_2 value for plotting the decision boundary."""
return 4 - np.sqrt(-x_1**2 + 4*x_1 + 6 + np.log(16))
# Generating a gaussion dataset:
# creating random vectors from the multivariate normal distribution
# given mean and covariance
mu_vec1 = np.array([0,0])
cov_mat1 = np.array([[2,0],[0,2]])
x1_samples = np.random.multivariate_normal(mu_vec1, cov_mat1,100)
mu_vec1 = mu_vec1.reshape(1,2).T # TO 1-COL VECTOR
mu_vec2 = np.array([1,2])
cov_mat2 = np.array([[1,0],[0,1]])
x2_samples = np.random.multivariate_normal(mu_vec2, cov_mat2, 100)
mu_vec2 = mu_vec2.reshape(1,2).T # to 2-col vector
# Main scatter plot and plot annotation
f, ax = plt.subplots(figsize = (7, 7))
ax.scatter(x1_samples[:, 0], x1_samples[:,1], marker = 'o',color = 'green', s=40)
ax.scatter(x2_samples[:, 0], x2_samples[:,1], marker = '^',color = 'blue', s =40)
plt.legend(['Class1 (w1)', 'Class2 (w2)'], loc = 'upper right')
plt.title('Densities of 2 classes with 25 bivariate random patterns each')
plt.ylabel('x2')
plt.xlabel('x1')
ftext = 'p(x|w1) -N(mu1=(0,0)^t, cov1 = I)\np.(x|w2) -N(mu2 = (1, 1)^t), cov2 =I'
plt.figtext(.15,.8, ftext, fontsize = 11, ha ='left')
#Adding decision boundary to plot
x_1 = np.arange(-5, 5, 0.1)
bound = decision_boundary(x_1)
plt.plot(x_1, bound, 'r--', lw = 3)
x_vec = np.linspace(*ax.get_xlim())
x_1 = np.arange(0, 100, 0.05)
plt.show()
image.png
- 直线划分
# 2-category classfication with random 2D-sample data
# from a multivariate normal distribution
import numpy as np
from matplotlib import pyplot as plt
def decision_boundary(x_1):
"""Calculates the x_2 value for plotting the decision boundary."""
# return 4 - np.sqrt(-x_1**2 + 4*x_1 + 6 + np.log(16))
return -x_1 + 1
# Generating a gaussion dataset:
# creating random vectors from the multivariate normal distribution
# given mean and covariance
mu_vec1 = np.array([0,0])
cov_mat1 = np.array([[2,0],[0,2]])
x1_samples = np.random.multivariate_normal(mu_vec1, cov_mat1,100)
mu_vec1 = mu_vec1.reshape(1,2).T # TO 1-COL VECTOR
mu_vec2 = np.array([1,2])
cov_mat2 = np.array([[1,0],[0,1]])
x2_samples = np.random.multivariate_normal(mu_vec2, cov_mat2, 100)
mu_vec2 = mu_vec2.reshape(1,2).T # to 2-col vector
# Main scatter plot and plot annotation
f, ax = plt.subplots(figsize = (7, 7))
ax.scatter(x1_samples[:, 0], x1_samples[:,1], marker = 'o',color = 'green', s=40)
ax.scatter(x2_samples[:, 0], x2_samples[:,1], marker = '^',color = 'blue', s =40)
plt.legend(['Class1 (w1)', 'Class2 (w2)'], loc = 'upper right')
plt.title('Densities of 2 classes with 25 bivariate random patterns each')
plt.ylabel('x2')
plt.xlabel('x1')
ftext = 'p(x|w1) -N(mu1=(0,0)^t, cov1 = I)\np.(x|w2) -N(mu2 = (1, 1)^t), cov2 =I'
plt.figtext(.15,.8, ftext, fontsize = 11, ha ='left')
#Adding decision boundary to plot
x_1 = np.arange(-5, 5, 0.1)
bound = decision_boundary(x_1)
plt.plot(x_1, bound, 'r--', lw = 3)
x_vec = np.linspace(*ax.get_xlim())
x_1 = np.arange(0, 100, 0.05)
plt.show()
image.png