Python 将元组列表排序到字典中时的奇怪计数行为

我已经研究这个问题好几个小时了，我想不出我的错误。这是Python代码（其中raw是元组列表，如[（2.0，'w'），（2.2，'WSW'），（4.5，'N'）…]）。第一个元组元素是表示风速的浮点。第二个是表示风向的字符串

bands = {'<0.5':[],'0.5-2':[],'2-4':[],'4-6':[],'6-8':[],'8-10':[],'10+':[]}
counts = {'<0.5':0,'0.5-2':0,'2-4':0,'4-6':0,'6-8':0,'8-10':0,'10+':0}
cardinals = {}
cardinal_count = {}
for item in raw:
  if not cardinals.has_key(item[1]):#wdir e.g. 'W'
    cardinals[item[1]] = bands
for item in cardinals.keys():
  if not cardinal_count.has_key(item):
    cardinal_count[item] = counts #

for speed,wdir in raw[:10]: # raw is very long - use only first ten for illustration
  target = cardinals[wdir]
  if speed < 0.5:
    cardinal_count[wdir]['<0.5'] += 1
  elif ((speed >= 0.5) and (speed < 2.0)):
    cardinal_count[wdir]['0.5-2'] += 1
  elif ((speed >= 2.0) and (speed < 4.0)):
    cardinal_count[wdir]['2-4'] += 1
  elif ((speed >= 4.0) and (speed < 6.0)):
    cardinal_count[wdir]['4-6'] += 1
  elif ((speed >= 6.0) and (speed < 8.0)):
    cardinal_count[wdir]['6-8'] += 1
  elif ((speed >= 8.0) and (speed < 10.0)):
    cardinal_count[wdir]['8-10'] += 1
  else:
    cardinal_count[wdir]['10+'] += 1
print cardinal_count
print raw[:10]

此处存在引用重复问题。当您将

条带

分配给许多不同的

基数[items[1]]

时，它们都会得到完全相同的条带字典；增加其中一条会增加所有其他条带字典。对于

计数

，也一样。您应该提供每个条带的副本，而不是原始条带

#at the top of your script:
from copy import deepcopy

#meanwhile, several lines down...
for item in raw:
  if not cardinals.has_key(item[1]):#wdir e.g. 'W'
    cardinals[item[1]] = deepcopy(bands)
for item in cardinals.keys():
  if not cardinal_count.has_key(item):
    cardinal_count[item] = deepcopy(counts) #

---

您能简化您的问题吗？请附上示例数据（如5个元素左右）、您的输出和预期输出。

for item in raw:
  if not cardinals.has_key(item[1]):#wdir e.g. 'W'
    cardinals[item[1]] = bands
for item in cardinals.keys():
  if not cardinal_count.has_key(item):
    cardinal_count[item] = counts #

#at the top of your script:
from copy import deepcopy

#meanwhile, several lines down...
for item in raw:
  if not cardinals.has_key(item[1]):#wdir e.g. 'W'
    cardinals[item[1]] = deepcopy(bands)
for item in cardinals.keys():
  if not cardinal_count.has_key(item):
    cardinal_count[item] = deepcopy(counts) #