python編程入門----matplotlib使用

1. matplotlib中的顏色映射（隨數值變換顏色深度）

#簡單使用plt畫圖
from matplotlib import pyplot as plt
input_num = list(range(0,50))
number = [x**2 for x in input_num]
#scatter()畫點陣圖,其中edgecolors是點邊緣，cmap是圖形顏色，
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)
#刻度參數
plt.tick_params(axis='both', labelsize=14)
#刻度範圍
plt.axis([0,50,0,2500])
plt.show()
plt.savefig('square_pigture.png', bbox_inches = 'tight')

2.隨機遊走的算法

• Random_walk.py

#encoding:utf-8
from random import choice
class RandomWalk():
    '''一個生成隨機漫步數據的類'''
    def __init__(self, num_points=5000):
        '''初始化隨機漫步的屬性'''
        self.num_points = num_points
# 全部隨機漫步都始於(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()
	#設置圖像畫布大小
    plt.figure(figsize=(10, 6))
	#爲後面顏色映射從小到大準備列表
    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")
	#隱藏行與列標
    plt.axes().get_xaxis().set_visible(False)
    plt.axes().get_yaxis().set_visible(False)
    plt.show()
    temp = raw_input("繼續請輸入True,不然False: ")
    print("\n")
    #plt.savefig("Random walk.png")
    if temp == "False":
        break