在使用matplotlib模块时画坐标图时，往往需要对坐标轴设置很多参数，这些参数包括横纵坐标轴范围、坐标轴刻度大小、坐标轴名称等
xlim():设置x坐标轴范围ylim():设置y坐标轴范围xlabel():设置x坐标轴名称ylabel():设置y坐标轴名称xticks():设置x轴刻度yticks():设置y轴刻度#创建数据x = np.linspace(-5, 5, 100)y1 = np.sin(x)y2 = np.cos(x)#创建figure窗口，figsize设置窗口的大小plt.figure(num=3, figsize=(8, 5))#画曲线1plt.plot(x, y1)#画曲线2plt.plot(x, y2, color='blue', linewidth=5.0, linestyle='--')#设置坐标轴范围plt.xlim((-5, 5))plt.ylim((-2, 2))#设置坐标轴名称plt.xlabel('xxxxxxxxxxx')plt.ylabel('yyyyyyyyyyy')#设置坐标轴刻度my_x_ticks = np.arange(-5, 5, 0.5)#对比范围和名称的区别#my_x_ticks = np.arange(-5, 2, 0.5)my_y_ticks = np.arange(-2, 2, 0.3)plt.xticks(my_x_ticks)plt.yticks(my_y_ticks)#显示出所有设置plt.show()
import matplotlib.pyplot as pltimport numpy as npx = np.linspace(-3, 3, 50)y1 = 2*x + 1y2 = x**2plt.figure()plt.plot(x, y2)plt.plot(x, y1, color='red', linewidth=1.0, linestyle='--')plt.xlim((-1, 2))plt.ylim((-2, 3))plt.xlabel('I am x')plt.ylabel('I am y')plt.show()x = np.linspace(-3, 3, 50)y1 = 2*x + 1y2 = x**2plt.figure()plt.plot(x, y2)plt.plot(x, y1, color='red', linewidth=1.0, linestyle='--')plt.xlim((-1, 2))plt.ylim((-2, 3))plt.xlabel('I am x')plt.ylabel('I am y')new_ticks = np.linspace(-1, 2, 5)print(new_ticks)plt.xticks(new_ticks)plt.yticks([-2, -1.8, -1, 1.22, 3],[r'$really\ bad$', r'$bad$', r'$normal$', r'$good$', r'$really\ good$'])plt.show()gca():获取当前坐标轴信息.spines:设置边框.set_color:设置边框颜色：默认白色.spines:设置边框.xaxis.set_ticks_position:设置x坐标刻度数字或名称的位置.yaxis.set_ticks_position:设置y坐标刻度数字或名称的位置.set_position:设置边框位置x = np.linspace(-3, 3, 50)y1 = 2*x + 1y2 = x**2plt.figure()plt.plot(x, y2)plt.plot(x, y1, color='red', linewidth=1.0, linestyle='--')plt.xlim((-1, 2))plt.ylim((-2, 3))new_ticks = np.linspace(-1, 2, 5)plt.xticks(new_ticks)plt.yticks([-2, -1.8, -1, 1.22, 3],['$really\ bad$', '$bad$', '$normal$', '$good$', '$really\ good$'])ax = plt.gca()#设置上边和右边无边框ax.spines['right'].set_color('none')ax.spines['top'].set_color('none')plt.show()ax = plt.gca()#设置上边和右边无边框ax.spines['right'].set_color('none')ax.spines['top'].set_color('none')#设置x坐标刻度数字或名称的位置ax.xaxis.set_ticks_position('bottom')#设置边框位置ax.spines['bottom'].set_position(('data', 0))plt.show()ax = plt.gca()#设置上边和右边无边框ax.spines['right'].set_color('none')ax.spines['top'].set_color('none')#设置x坐标刻度数字或名称的位置ax.xaxis.set_ticks_position('bottom')#设置边框位置ax.spines['bottom'].set_position(('data', 0))ax.yaxis.set_ticks_position('left')ax.spines['left'].set_position(('data',0))plt.show()matplotlib.pyplot.text(x, y, s, fontdict=None, withdash=False, **kwargs)x, y：表示坐标；s：字符串文本；fontdict：字典，可选；kw：fontsize=12,horizontalalignment=‘center’、ha=’cener’verticalalignment=’center’、va=’center’#!/usr/bin/python#coding: utf-8import numpy as npimport matplotlib.pyplot as pltx = np.arange(-10, 11, 1) #形成一个数组，第三个参数表示步长，#start,end,stepy = x ** 2plt.plot(x, y)# 第一个参数是x轴坐标# 第二个参数是y轴坐标# 第三个参数是要显式的内容# alpha 设置字体的透明度# family 设置字体# size 设置字体的大小# style 设置字体的风格# wight 字体的粗细# bbox 给字体添加框，alpha 设置框体的透明度， facecolor 设置框体的颜色plt.text(-3, 20, "function: y = x * x", size = 15, alpha = 0.2)plt.text(-3, 40, "function: y = x * x", size = 15, family = "fantasy", color = "r", style = "italic", weight = "light", bbox = dict(facecolor = "r", alpha = 0.2))plt.show()# -*- coding: utf-8 -*-import timeimport matplotlib.pyplot as pltdef showResult(xList, yList, title, xLabel, yLabel): plt.plot(xList, yList, 'g*-') plt.title(title) plt.xlabel(xLabel) plt.ylabel(yLabel) for x, y in zip(xList, yList): plt.text(x, y+0.3, str(y), ha='center', va='bottom', fontsize=10.5) plt.savefig('fig'+str(int(time.time()))+'.jpg') plt.show()x_arr = [1, 2, 3, 4, 5, 6]y_arr = [1, 4, 9, 16, 25, 36]showResult(x_arr, y_arr, 'title', 'x', 'y')其中
for x, y in zip(xList, yList):plt.text(x, y+0.3, '%.0f'%y, ha='center', va='bottom', fontsize=10.5)逐个获取需要标注的点的横纵坐标 x与 y，然后在位置 (x, y+0.3) 处以 10.5 的字体显示出 y 的值，‘center’ 和 ‘bottom’ 分别指水平和垂直方向上的对齐方式。
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