Team, The piece of code below is giving me an error which I can't find the solution. The assignment below for * msgCount[r][c] = mtc *is trwoing an exception. which I list below. Any suggestions? ################################################################### #Date READ ENTRY DELETE ALARM HOTLIST SITE # #20130611 2000000 200000 200000 2000 2000 20000 # #20130611 2000000 200000 200000 2000 2000 20000 # ################################################################### msgCount = Array.new # Empty array. Will have size of [r][7]. Rows will grow fn = "/home/rb/MyData/dp/PR_LOGS/pr_time.log.*" msgTypes = ["read", "entry", "delete", "alarm", "hotlist", "site"] fnls = `ls #{fn}`.split # Create fnls = file names list fc = fnls.size # Number of files to be processed fnls.each do |f| # Process each file r = 0 # Rows are controlled by fnls, number of files lp,lg,dt = f.split('.') # this info will be used later 7.times do |c| # Process each column mtc = `grep #{msgTypes[c]} #{f} | wc -l` # Get Message Type Count *msgCount[r][c] = mtc* r += 1 # Next row please end end *in `block (2 levels) in <main>': undefined method `[]=' for nil:NilClass (NoMethodError)* Thank you -- Ruby Student