Hello I have analyzed my microarray data using R language , and my final data including p-value and fold change is ready. I am used to save the data as an excel file to sort my data. However, this time I want to try to obtain these data using R. How can I obtain data from this table with the following conditions:

- p-value < 0.05
- logfc >1.2 or <-1.2

Also, I was wondering to know what is the difference between p-value and adjusted p-value in expression studies results?

Thanks for your help. Should I add the other rule with &? I mean log fc Higher than 1.2 or lower that -1.2. How should I say this? Also, I found an instruction which used "topTable" from limma package. The point is that I should define an 'Absolut fold change' to it. What is Absolut fold change?

My command already has both cases for fold change covered, as it uses the

`abs()`

function to get the absolute values of the fold change column. Therefore, any negative value will be made positive, thus allowing the values between -1.2 and 1.2 to be properly ignored. If the`abs`

function wasn't being used, then yes, you could include the rule for the opposite direction as well, e.g.:`df <- df[df$p < 0.05 & df$logfc > 1.2 & df$logfc < -1.2,]`

Thanks a lot. Interestingly, when I try to obtain my data using such codes, I get no results in response. However, when I save my table as an excel file, there are plenty of genes with my criteria. I think your first suggestion about avoiding post-hoc filtering is the answer.