''' Purpose: introductory take on examining a table of values
'''

# MAKE SURE YOU RECOGNIZE THIS
# define table / dataset
# a table is a list of lists !!!
# each sublist = row
# each row = column/element in that sublist
table = [ [ "A", "B", "C" ], [ "D", "E", "F" ], [ "G", "H", "I" ], [ "J", "K", "L", "M" ] ]

# table[0] is a list in itself --> ['A', 'B', 'C']

print( "table:", table )

print()

# determine number of rows in table
# for a list of lists, the number of elements is how many sublists there are in the biggest list
# aka how many rows are there in the table/dataset
nrows = len( table )

# if we find the len( a_row ) --> tells us the number of columns in that row a_row
# each row does not have to have the same number of columns

print( "the table has", nrows, "rows" )

print()

# print each row of the table along withs number of columns
# row is not a keyword, we're just calling it row because it represents a sublist in the table
# which we refer to as a "row"
for row in table :
    print( row )
    ncols = len( row )      # since row is a list in itself, we can use len() to find the number of elements
                            # or number of columns in this row
    # print( "row", row, "has", ncols, "columns" )

    # 1st time: row = ['A', 'B', 'C'] --> this is a LIST!!! --> can use len() to find the number of things
    #   in this list (which is 3)! the number of elements in each of these sublist is also the number of columns!
    # 2nd time: row = ['D', 'E', 'F'] --> same process
    # so on

# going through one for loop in a table always processes each row in that table

print()

# print each row of the table using row indices
# remember range of indices always starts at 0 and go up to but not including the length of the list
for r in range( 0, nrows ) :
    row = table[ r ]                # get current index of the table --> the element at each index is a list/row
                                    # we can also get a specific element from a list using the [] notation
                                    # in between the [] is the index/position in the list you want to peek into
    print( "row", r, ":",  row )