python plt 画散点图

在做PAT的几何题是，为了方面看图，用一下python

读取文件x，y

import matplotlib.pyplot as plt
import numpy as np
with open("map.txt") as f:
    lines = f.readlines()
    n = int(lines[0])
    x = []
    y = []
    for i in range(n):
        line = lines[i+1].split(" ")
        x.append(int(line[0]))
        y.append(int(line[1]))
#                   记号形状       颜色           点的大小    设置标签
plt.scatter(x, y, marker = 'x',color = 'red', s = 40 ,label = 'First')
plt.legend(loc = 'best')    # 设置 图例所在的位置 使用推荐位置
plt.show()