How to create a loop that runs through the rows of a table?

Question

Harry Jones 2021-3-16

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/774682-how-to-create-a-loop-that-runs-through-the-rows-of-a-table

评论： Cris LaPierre 2021-3-16

I am trying to create a loop that runs through a table (2016 x 2) that takes the data from each column and inputs it into an equation and plots each result for each row. This is what I have attempted so far however, I am struggling to get this to work. Any help would be greatly appreciated.

rows = height(T);
for row = 1:rows 
    a1=T(row,1);
    a2=T(row,2);
    P=a1*a2;
end
hold on 
plot(p,row)

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Answer 1

Cris LaPierre 2021-3-16

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https://ww2.mathworks.cn/matlabcentral/answers/774682-how-to-create-a-loop-that-runs-through-the-rows-of-a-table#answer_649432

编辑：Cris LaPierre 2021-3-16

在 MATLAB Online 中打开

You don't need a for loop for this.

P=T{:,1}.*T{:,2};
plot(P)

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Harry Jones 2021-3-16

T is the table of variables I plan to use. a1 refers to the column a and a2 refers to column B. It should now be attached. Thanks once again for looking at this!

Cris LaPierre 2021-3-16

在 MATLAB Online 中打开

T.xlsx

You need to capture the result from each loop. Right now, each loop overwrites the previous value with the current value. You want to keep them all.

T=readtable("T.xlsx")

T = 2116×2 table

Var1 Var2 ____ ____ 30 30 30 31 30 32 30 33 30 34 30 35 30 36 30 37 30 38 30 39 30 40 30 41 30 42 30 43 30 44 30 45

E1=236;

E2=5;

G12=2.6;

v12=0.25;

v21=(v12*E2)/E1;

t=0.25;

N1=[1.5;3;0];

Q=[(E1/(1-v12*v21)) ((v12*E2)/(1-v12*v21)) 0; ((v21*E1)/(1-v12*v21)) (E2/(1-v12*v21)) 0; 0 0 G12];

rows = height( T);

Z1=0;

Z2=t;

Z3=2*t;

Z4=3*t;

Z5=4*t;

for row = 1:1:rows

a1=T{row,1};

a2=T{row,2};

%Matricies definition

T1=[cosd(a1)^2, sind(a1)^2, -2*cosd(a1)*sind(a1); sind(a1)^2, cosd(a1)^2, 2*cosd(a1)*sind(a1); cosd(a1)*sind(a1), -cosd(a1)*sind(a1), (cosd(a1)^2-sind(a1)^2)];

T2=[cosd(a2)^2, sind(a2)^2, -2*cosd(a2)*sind(a2); sind(a2)^2, cosd(a2)^2, 2*cosd(a2)*sind(a2); cosd(a2)*sind(a2), -cosd(a2)*sind(a2), (cosd(a2)^2-sind(a2)^2)];

Q1=T1*Q*transpose(T1);

Q2=T2*Q*transpose(T2);

A=(Q1*(Z2-Z1))+(Q2*(Z3-Z2))+(Q1*(Z4-Z3))+(Q2*(Z5-Z4));

B=(0.5*Q1*((Z2^2)-(Z1^2)))+(0.5*Q2*((Z3^2)-(Z2^2))+(0.5*Q1*(Z4^2)-(Z3^2)))+(0.5*Q2*((Z5^2)-(Z4^2)));

D=((1/3)*Q1*((Z2^3)-(Z1^3)))+((1/3)*Q2*((Z3^3)-(Z2^3))+((1/3)*Q1*(Z4^3)-(Z3^3)))+((1/3)*Q2*((Z5^3)-(Z4^3)));

e0=(A^-1)*N1;

e1=(transpose(T1))*e0;

e2=(transpose(T2))*e0;

s1=Q*e1;

s2=Q*e2;

sx1(row)=s1(1,1);

sy1(row)=s1(2,1);

end

plot(sx1,sy1,'.')

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Answer 2

ANKUR KUMAR 2021-3-16

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https://ww2.mathworks.cn/matlabcentral/answers/774682-how-to-create-a-loop-that-runs-through-the-rows-of-a-table#answer_649442

编辑：ANKUR KUMAR 2021-3-16

在 MATLAB Online 中打开

clc
clear
A=randi(20,25,5); %generating random data
T = array2table(A);
equation= @(x) x*5 + log(x) % creating an equation
names=T.Properties.VariableNames;
for kk=1:length(names)
	values=T(:,names{kk});
	plot(equation(values{:,:}))
	hold on
	
end