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Hello all, I have written a for loop to act on a dataframe with close to 3million rows and 6 columns and I would like to pass it to apply() to speed the process up (I let the loop run for 2 days before stopping it and it had only gone through 200,000 rows) but I am really struggling to find a way to pass the arguments. Below are the loop and the head of the dataframe I am working on. Any hints

Hi all, I have some microarray data on 40 samples that fall into two groups. I have a value for 480k probes for each of those samples. I performed a t test (rowttests) on each row(giving the indices of the columns for each group) then used p.adjust() to adjust the pvalues for the number of tests performed. I then selected only the probes with adj-p.value<=0.05. I end up with roughly 2000

Hi, I have a matrix (pwdiff in the example below) with ~480000 rows and 780 columns. For each row, I want to get the percentage of columns that have an absolute value above a certain threshold "t". I then want to allocate that percentage to matrix 'perc' in the corresponding row. Below is my attempt at doing this, but it does not work: I get 'replacement has length