1、将数组中小于某个值得数全部加上某个值:
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| theta3(theta3(:)<0)=theta3((theta3(:)<0))+360
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2、规定图像范围,改变x轴标记:
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| axis([80,440,-2.5,3.5]); set(gca, 'Xtick',80:30:440) set(gca,'Xticklabel',{'80\circ','110\circ','140\circ','170\circ','200\circ','230\circ','260\circ','290\circ','320\circ','350\circ','20\circ','50\circ','80\circ',})
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3、将x作图曲线从大到小排列
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| set(gca,'XDir','reverse')
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4、取整函数
· 1、fix(x):截尾取整;
· 2、floor(x):不超过x的最大整数;
· 3、ceil(x):不大于x的最小整数;
· 4、round(x):四舍五入取整;
5、自动保存图片
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| for t=1:n h=figure(t); plot(Ci,Cj,'R*-'); name=['figure',num2str(t),'.jpg']; saveas(h,name); end
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6、矩阵标准化
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| a=xlsread('D:\File\文档\MATLAB\A.xlsx','Sheet5','A1:D13'); [A,A_mean,A_std]=zscore(a) B=xlsread('D:\File\文档\MATLAB\A.xlsx','Sheet4','A1:C4') c=A*B; C=B'./A_std
syms X1 X2 X3 X4 F1 F2 F3
F1=C(1,1)*(X1-A_mean(1))+C(1,2)*(X2-A_mean(2))+C(1,3)*(X3-A_mean(3))+C(1,4)*(X4-A_mean(4)); F2=C(2,1)*(X1-A_mean(1))+C(2,2)*(X2-A_mean(2))+C(2,3)*(X3-A_mean(3))+C(2,4)*(X4-A_mean(4)); F3=C(3,1)*(X1-A_mean(1))+C(3,2)*(X2-A_mean(2))+C(3,3)*(X3-A_mean(3))+C(3,4)*(X4-A_mean(4));
y=95.423+9.883*F1+0.125*F2+4.555*F3;
Y=vpa(y,4)
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A_mean
: 均值
A_std
: 标准方差
vpa
函数:
- 1、控制精度,上述控制结果精度为4。
- 2、求根,上述已知X & F关系,将以F为自变量转换为以X为自变量。
7、求元素在数组中出现的频率
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| [ID,A]=xlsread('D:\File\微云同步\数学建模\4数据挖掘\processedfile.xlsx') B1=tabulate(A(2:end,1))
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8、Matlab打开网页
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| web browser tuoxiao.github.io
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