use zip
columns = zip(*rows) #transpose rows to columns
print columns[0] #print the first column
#you can also do more with the columns
print columns[1] # or print the second column
columns.append([7,7,7]) #add a new column to the end
backToRows = zip(*columns) # now we are back to rows with a new column
print backToRows
you can also use numpy
a = numpy.array(a)
print a[:,0]
Edit: zip object is not subscriptable. It need to be converted to list to access as list:
column = list(zip(*row))