enumerate(iter, start=0)
for item in enumerate(['subject', 'verb', 'object']):
... print(item)
(0, 'subject')
(1, 'verb')
(2, 'object')
f = open('data.txt', 'r')
for i, line in enumerate(f):
if line.strip() == '':
print('Blank line at line #%i' % i)