Hi,

i am not very good at pseudocode

Oh, dear. pseduocode == clear thinking. You're gonna need that.

Try starting this way: on a piece of paper, using an analogue writing device, set down the steps you would take to solve the problem using math. Your problem definition has the skeleton answer already.

(note use of BASIC line numbering to allow for inserted steps, lol)

100. for each row, calculate the mean of the values.
     
     
200. The output should be a list of genes and their respective mean expression value.

Now fill in the sub-steps. To calculate the mean for a row, what do you have to do first? Maybe reading the row is a prerequisite to doing the calculation?

(Possibly of interest: How to teach programming with a peanut butter and jelly sandwich)

Hope this helps!