names = ['Alice', 'Bob', 'Carl', 'Dave', 'Bob', 'Earl', 'Carl', 'Frank', 'Carl'
    ]
counter = collections.Counter(names)
print('Counter: %s' % counter)
result = []
for name, counts in counter.items():
    if counts == 1:
        result.append(name)
else:
    for i in range(counts):
        result.append('%s_%d' % (name, i + 1))
print(result)
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