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

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FortuitousMonkey on 13 Jun 2018
Commented: ssg on 8 Feb 2021
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 on 13 Jun 2018
Not sure what your question means?

Star Strider on 13 Jun 2018
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’
Nev on 29 May 2019
Edited: Nev on 29 May 2019
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 on 8 Feb 2021
I too have the same problem as mentioned by @Nev. Any suggestions about it ?

sura Naji on 25 Oct 2019
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