python编程入门----matplotlib使用

1. matplotlib中的颜色映射（随数值变换颜色深度）

#简单使用plt画图
from matplotlib import pyplot as plt
input_num = list(range(0,50))
number = [x**2 for x in input_num]
#scatter()画点阵图,其中edgecolors是点边缘，cmap是图形颜色，
plt.scatter(input_num, number, s=40, edgecolors ='none', c=number, cmap=plt.cm.Blues)
#plt.plot(input_num, number, linewidth = 3)
plt.title("square_number",fontsize = 24 )
plt.xlabel("x_num", fontsize = 14)
plt.ylabel("y_result", fontsize = 14)
#刻度参数
plt.tick_params(axis='both', labelsize=14)
#刻度范围
plt.axis([0,50,0,2500])
plt.show()
plt.savefig('square_pigture.png', bbox_inches = 'tight')

2.随机游走的算法

• Random_walk.py

#encoding:utf-8
from random import choice
class RandomWalk():
    '''一个生成随机漫步数据的类'''
    def __init__(self, num_points=5000):
        '''初始化随机漫步的属性'''
        self.num_points = num_points
# 全部随机漫步都始于(0, 0) 
        self.y_values = [0]
        self.x_values = [0]
    def fill_walk(self):
        while self.num_points > len(self.x_values):
            x_direction = choice([-1, 1])
            x_step = choice([0, 1, 2, 3, 4])
            x = x_direction * x_step
            y_direction = choice([-1, 1])
            y_step = choice([0, 1, 2, 3, 4])
            y = y_direction * y_step
            if x_step == 0 and y_step == 0:
                continue
            next_x = self.x_values[-1] + x
            next_y = self.y_values[-1] + y
            self.y_values.append(next_y)
            self.x_values.append(next_x)

1. walk.py

from matplotlib import pyplot as plt
from random_walk import RandomWalk
while True:
    rw = RandomWalk()
    rw.fill_walk()
	#设置图像画布大小
    plt.figure(figsize=(10, 6))
	#为后面颜色映射从小到大准备列表
    point_numbers = list(range(rw.num_points))
    plt.scatter(rw.x_values, rw.y_values, c=point_numbers, cmap=plt.cm.Blues, edgecolor='none', s=15)
   # plt.plot(rw.x_values, rw.y_values, linewidth=5)
    plt.scatter(0, 0, c='red', edgecolors='none', s=100)
    plt.scatter(rw.x_values[-1], rw.y_values[-1], c='red', edgecolors='none',s=50)
    plt.title("Ramdom_walk")
	#隐藏行与列标
    plt.axes().get_xaxis().set_visible(False)
    plt.axes().get_yaxis().set_visible(False)
    plt.show()
    temp = raw_input("继续请输入True,不然False: ")
    print("\n")
    #plt.savefig("Random walk.png")
    if temp == "False":
        break