How to create a function which takes one column of data as its input and another as its output

I have two columns of data and need to come up with a function that take as input the values from the first column of data and outputs the corresponding values in the second column. There is no equation that links the columns together they are just two lines of data. How would I go about coming up with a function that enables me to input a value from the first column and be given the corresponding value in the second?

[Dyuman Joshi]

"... outputs the corresponding values in the second column."

You want to store the output in the second column, over-writing the values present there?

[Gabriel]

No so for example column 1 row 6 will correspond to column 2 row 6 and column 1 row 10 corresponds to column 2 row 10. I need a function that allows me to input the values in column 1 and get the value next to it in column 2 as my output. I hope that makes sense

Answer 1

[David Hill]

Just use the find function. find

rng(1)
A=randi(100,10,2)

A = 10×2

42 42 73 69 1 21 31 88 15 3 10 68 19 42 35 56 40 15 54 20

f=A(find(A(:,2)==88),1)

f = 31

[Gabriel]

Thank you very much! I thought it was probably read but didn’t quite know how to put it all together

[Stephen23]

Logical indexing is simpler than FIND:

rng(1)
A = randi(100,10,2)

A = 10×2

42 42 73 69 1 21 31 88 15 3 10 68 19 42 35 56 40 15 54 20

V = 88;
Z = A(A(:,2)==88,1)

Z = 31

[David Hill]

Yes