#Author:  James Tam
#Version: October 31, 2025 (Boo!)
#Learning objective (extra practice for 2D lists since there haven't been
#a great deal of opportunity to do this with existing graded components).
#Writing code: Iterating a 2D list, accessing list elements




aList = [[2,-2,2,-2],
         [1,-1,1,-1]]

numRows = len(aList)

#List is rectangular and a 2D list consists of rows of 1D lists so the width
#of any row is the number of columns.
numColumns = len(aList[0])

r = 0
total = 0
while(r<numRows):
    c = 0
    while(c<numColumns):
        total = total + aList[r][c]
        c = c + 1
    r = r + 1
r = 0

theAverage = total/(numRows*numColumns)
#\t is the tab esccape code, the slash followed by one of the escape codes specifies
#the formatting of text in a string, in this case \t=TAB
print("Total:",total,"\tAverage:", theAverage)