使用字典来存储计数器:
data = """Los Angeles California
San Diego California
San Francisco California
Albany New York
Buffalo New York
Orlando Florida""".splitlines()
counters = {}
for line in data:
city, state = line[:14], line[14:]
# city, state = line.split('\t') # if separated by tabulator
if state not in counters:
counters[state] = 1
else:
counters[state] += 1
print counters
# {'Florida': 1, 'New York': 2, 'California': 3}
您可以通过使用来简化它collections.defaultdict
:
from collections import defaultdict
counter = defaultdict(int)
for line in data:
city, state = line[:14], line[14:]
counter[state] += 1
print counter
# defaultdict(<type 'int'>, {'Florida': 1, 'New York': 2, 'California': 3})
或使用collections.Counter
和生成器表达式:
from collections import Counter
states = Counter(line[14:] for line in data)
# Counter({'California': 3, 'New York': 2, 'Florida': 1})