How can I create a function that inputs a row

I need to create a function which takes the following input

1. a row

im extremely confused and no data is required to answer this right now.

do i put

[madhan ravi]

what have you tried so far? upload your code

[madhan ravi]

m2 = vec2mat ([1:25],5) %why is this used?

[Guillaume]

Please, do not close questions for which you have received extensive feedback (and help). Talking of rudeness, that is particularly rude to those who spent time trying to help you.

edit: and removing all the meaningful part of your question is only going to anger us (and we'll ask Mathworks to restore your question anyway) and unlikely that you'll receive any help in the future. Akcnowledging that you've received help and are willing to learn from it, on the other hand, make it more likely that we'll still help you.

[Fope Ayo]

ok

Answer 1

[Luna]

Hi,

Your return value should be written like below for functions.

Your inputs should be written inside the paranthesis.

function rowSum = myMatrixFunc(A,rowNumber)

rowSum = sum(A(rowNumber,:));

end

[Fope Ayo]

thanks for this but when recalling the function, how do i enter the letter to put in the output

[Stephen23]

"...but when recalling the function, how do i enter the letter to put in the output "

What is "the letter to put in the output" ?

[Fope Ayo]

By this i mean, how do i write sum when recalling the function in my script?

Say I use the above code:

function rowSum = myMatrixFunc(A,rowNumber)
rowSum = sum(A(rowNumber,:));
end

Example
G = [1 2 3; 4 5 6; 7 8 9] %matrix
myMatrixFunc (G, 1, 1:3)

This evidently results in error. So what do I do now?

[madhan ravi]

G = [1 2 3; 4 5 6; 7 8 9] %correct usage 
Result=myMatrixFunc (G, 1:3)     %function calling

function rowSum = myMatrixFunc(A,rowNumber)  %function definition
rowSum = sum(A(rowNumber,:));
end

[Fope Ayo]

THANK YOU SO MUCH!

BUT this does not work for my question completely.

I need to calculate the sum for a row not the column, could you correct that for me if possible?

[Guillaume]

A(rownumber, :) is a row of A. So summing that is going to be the sum for a row. If you want the sum for a column, (i.e. sum across all the rows), then:

function colSum = myMatrixFun(A, colNumber)
    colSum = sum(A(:, colNumber));
end

If your definition of the sum for row (or column) differs from the above then you need to explain clearly what it is.

Answer 2

[Dennis]

You can read about functions here.

function res=myfunc(matrix,row)
%function [output1,output2]=functionname(input1,input2)
res=sum(matrix(row(row,:)));
end

[Fope Ayo]

thanks for this but how can i write sum in the equation when recalling the function?

[madhan ravi]

what equation??

[Fope Ayo]

function [matrix,rowNumber]=myfunc2 (matrixrow)
matrixrow = sum (matrix(rownumber, :))
end

[Dennis]

After you saved the function and added it to matlabs search path you can call the function from the command line or any other function/script.

Example:

A=randi(100,25,10); %matrix
mysum=myfunc(A,5)

[Fope Ayo]

What is res in the code you gave me?

[Dennis]

Please check the link in my answer and learn the basics about functions in matlab.

The names of input/output arguments inside a function have nothing to do with variablenames outside that function. 'res' only exists in myfunc, it is the output that function provides.

When you call myfunc you can provide a variable where you want to store the output, but this is completly independant from any variable names used inside the function.

Answer 3

[Fope Ayo]

the answers did not fix my ‘buggy’ function. is there a need to be so rude?

[Guillaume]

The answers did show you the correct syntax. In addition, Dennis' one gave you a link to the documentation that clearly explains how to write functions. Then you come back with:

function [matrix,rowNumber]=myfunc2 (matrixrow)

which has inputs where outputs should be and outputs where inputs should be, so clearly you've failed to grasp even the basics of writing functions. Your further questions showed that you do not understand how to call functions since in one of your comments, you provide 3 inputs to a function that only takes 2.

We don't mind helping you but at some point you need to read the documentation to learn the basics.

[Fope Ayo]

No this is the first time i've used matlab so yes I am just learning, i have read the basics but it was a little confusing when relating it to my question. Nevertheless, thanks for the help.