matplotlib基础3：散点图scatter图形和polar坐标图绘制及方法属性简述（希腊字母表示方法 r'$ name_ $'）

散点图scatter

NOTE: plt.scatter(… c=d, cmap='bwr_r'…)

c=d, cmap='jet': 渐变颜色映射
cmap_list元素后面加'_r'表示逆向渐变，如 bwr蓝白红 ---> bwr_r 红白蓝

渐变颜色映射表链接：color example code: colormaps_reference.py

# -*- coding: utf-8 -*-
"""
Created on Thu Jul 26 08:57:40 2018

@author: Administrator
"""

import numpy as np
import matplotlib.pyplot as plt

n = 2000
x = np.random.normal(0,1,n)     # 标准正态分布
y = np.random.normal(0,1,n)
d = np.sqrt(x**2 + y**2)    # 点距离(0,0)的距离，距离远近用渐变色反映出来
# Square Root Calculations : np.sqrt(x) / math.sqrt(x) 平方根运算
# Square ： pow(x,2) /  np.square平方运算

plt.figure('Scatter', facecolor='lightgray')
plt.title('Scatter', fontsize=16)
plt.xlabel('x', fontsize=14)
plt.ylabel('y', fontsize=14)
plt.tick_params(labelsize=10)
plt.grid(linestyle=':', axis='x')

# 注意：scatter的size和color 只能用简写的's'和'c'，全称会报错unknow property
plt.scatter(x, y,               # date positions 坐标(x, y)
            marker='o',         # 散点样式，default: 'o'
            s=30,               # 不能用 'size',scalar or array_like, shape (n, ), optional
            c=d,                # 不能用'color';颜色：渐变色，传入距离d，渐变色映射距离远近
            cmap='jet_r',       # 颜色映射，only used if 'c' is an array of floats
            linewidths=0.5,     # (复数s，不是单数):linewidth of marker edges. 
            edgecolors='r',     # (复数s，不是单数) 默认'face' 与c一样 / A matplotib color / None
            alpha=0.5           # 透明度
            )
'''
c=d, cmap='jet': 渐变颜色映射
渐变颜色映射表链接：https://matplotlib.org/examples/color/colormaps_reference.html
cmap_list元素后面加'_r'表示逆向，如 bwr蓝白红 ---> bwr_r 红白蓝
'''
plt.show()


# bolow scatter attrabutes:
'''
def 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)

cmap : `~matplotlib.colors.Colormap`, optional, default: None
        A `.Colormap` instance or registered colormap name. *cmap* is only
        used if *c* is an array of floats. If ``None``, defaults to rc
        ``image.cmap``.

'''

---

折线图：
'''
plot(*args, **kwargs)
    Plot y versus x as lines and/or markers.
    Call signatures:
        plot([x], y, [fmt], data=None, **kwargs)
        plot([x], y, [fmt], [x2], y2, [fmt2], ..., **kwargs)
'''

极坐标图

# -*- coding: utf-8 -*-
"""
Created on Tue Aug  7 12:54:37 2018

@author: Administrator
"""

import numpy as np
import matplotlib.pyplot as mp

t = np.linspace(0, 6 * np.pi, 1001)     # 极角
r_spiral = 0.8 * t                      # 极距
r_rose = 5 * np.sin(6 * t)              # 极距

mp.figure('Polar', facecolor='lightgray')
mp.gca(projection='polar')              # 获取极坐标轴，默认是2d坐标轴
mp.title('Polar', fontsize=20)
mp.xlabel(r'$\theta$', fontsize=14)     # 希腊字母表示方式：r'$ name_ $'
mp.ylabel(r'$\rho$', fontsize=14)       # # 希腊字母表示方式：r'$ name_ $'
mp.tick_params(labelsize=10)
mp.grid(linestyle=':')

mp.plot(t,                              # 极角
        r_spiral,                       # 极距
        c='dodgerblue',
        label=r'$\rho=0.8\theta$'       # 标签，留意表示方法 r'$\rho=0.8\theta$'
        )

mp.plot(t, 
        r_rose, 
        c='orangered',
        label=r'$\rho=5sin(6\theta)$'
        )

mp.legend(loc='lower left')
mp.show()