Find the mean of values in a column when a condition is met

I am processing some data in matlab from excel.

The data is in matrix form (used read function).

I need to find the average of column c when column a value for the corresponding row is = to somevalue.

If I were to do this in excel I would use AVERAGEIF(A:A,=650,C:C) and it calculates the correct results. However I don't know how to replicate this statement in matlab.

Ideally the output would be in matrix form. Although I've attached a picture of excel data of a few words. The information I need to process is likely going to be 1000-3000 x 40 matrix.

Any thoughts?

[FortuitousMonkey]

Not sure what your question means?

Answer 1

[Star Strider]

Try this:

M = randi(9, 10, 3)                                     % Create Matrix
someValue = 3                                           % Define ‘somevalue’
C_mean = mean(M(M(:,1) == someValue, 3))                % Mean Of Column #3 For Column #1 = ‘somevalue’

[FortuitousMonkey]

This works. Thanks, I'll implement it and how I get on.

[Star Strider]

As always, my pleasure.

[Nev]

Hi, I have a similar problem but the "some value" needs to be a range so:

If column 1 is between value 1 and value 2 (e.g. 2.000 - 2.999) then average the values in column 2.

somevalue = 2.000:2.999; <-- this doesnt seem to work and I am not sure how to tell it to include all numbers inbetween.

Any help would be much appreciated!

[ssg]

I too have the same problem as mentioned by @Nev. Any suggestions about it ?

Answer 2

[sura Naji]

l have amatrix contact from 1 colum and 1000 rows l want to find the mean and the standard deviation also l want to find the worst value of this because l use the particle swarm optimization