小写字典键和值

Question

我有一个函数，对于不区分大小写的键和 US_STATES 的值，应该返回 true

from localflavor.us.us_states import US_STATES

def check_state(value):
    return value in dict(US_STATES).values())
print(US_STATES)

结果是：

(('AK', 'Alaska'), ('AL', 'Alabama'), ('AR', 'Arkansas'), ('AZ', 'Arizona'), ('CA', 'California'), ('CO', 'Colorado'), ('CT', 'Connecticut'), ('DC', 'District of Columbia'), ('DE', 'Delaware'), ('FL', 'Florida'), ('GA', 'Georgia'), ('HI', 'Hawaii'), ('IA', 'Iowa'), ('ID', 'Idaho'), ('IL', 'Illinois'), ('IN', 'Indiana'), ('KS', 'Kansas'), ('KY', 'Kentucky'), ('LA', 'Louisiana'), ('MA', 'Massachusetts'), ('MD', 'Maryland'), ('ME', 'Maine'), ('MI', 'Michigan'), ('MN', 'Minnesota'), ('MO', 'Missouri'), ('MS', 'Mississippi'), ('MT', 'Montana'), ('NC', 'North Carolina'), ('ND', 'North Dakota'), ('NE', 'Nebraska'), ('NH', 'New Hampshire'), ('NJ', 'New Jersey'), ('NM', 'New Mexico'), ('NV', 'Nevada'), ('NY', 'New York'), ('OH', 'Ohio'), ('OK', 'Oklahoma'), ('OR', 'Oregon'), ('PA', 'Pennsylvania'), ('RI', 'Rhode Island'), ('SC', 'South Carolina'), ('SD', 'South Dakota'), ('TN', 'Tennessee'), ('TX', 'Texas'), ('UT', 'Utah'), ('VA', 'Virginia'), ('VT', 'Vermont'), ('WA', 'Washington'), ('WI', 'Wisconsin'), ('WV', 'West Virginia'), ('WY', 'Wyoming'))

此函数返回 true仅适用于值，但我还需要为状态代码的键返回 true ，并且该函数应为不区分大小写的键值对返回 true 。

Answer 1

我没有使用 Django（你显然是这样），所以让我们从基础开始：

STATES = (('AK', 'Alaska'), ('AL', 'Alabama'), ('AR', 'Arkansas'), ('AZ', 'Arizona'), ('CA', 'California'), ('CO', 'Colorado'), ('CT', 'Connecticut'), ('DC', 'District of Columbia'), ('DE', 'Delaware'), ('FL', 'Florida'), ('GA', 'Georgia'), ('HI', 'Hawaii'), ('IA', 'Iowa'), ('ID', 'Idaho'), ('IL', 'Illinois'), ('IN', 'Indiana'), ('KS', 'Kansas'), ('KY', 'Kentucky'), ('LA', 'Louisiana'), ('MA', 'Massachusetts'), ('MD', 'Maryland'), ('ME', 'Maine'), ('MI', 'Michigan'), ('MN', 'Minnesota'), ('MO', 'Missouri'), ('MS', 'Mississippi'),
          ('MT', 'Montana'), ('NC', 'North Carolina'), ('ND', 'North Dakota'), ('NE', 'Nebraska'), ('NH', 'New Hampshire'), ('NJ', 'New Jersey'), ('NM', 'New Mexico'), ('NV', 'Nevada'), ('NY', 'New York'), ('OH', 'Ohio'), ('OK', 'Oklahoma'), ('OR', 'Oregon'), ('PA', 'Pennsylvania'), ('RI', 'Rhode Island'), ('SC', 'South Carolina'), ('SD', 'South Dakota'), ('TN', 'Tennessee'), ('TX', 'Texas'), ('UT', 'Utah'), ('VA', 'Virginia'), ('VT', 'Vermont'), ('WA', 'Washington'), ('WI', 'Wisconsin'), ('WV', 'West Virginia'), ('WY', 'Wyoming'))

statesByCode = {k.lower(): v.lower() for k, v in STATES} # keyed on lowercase state code
statesByState = {v.lower(): k.lower() for k, v in STATES} # keyed on lowercase state name

只需创建两个字典，其中键的“正常形式”为小写。一本字典以州代码为关键字，另一本字典以州名称为关键字。

然后您可以这样做：

def check_state(value):
  return value.lower() in statesByCode

因此您可以轻松（并且非常快速）检查给定的状态代码是否有效。

例如，

check_state('Co')

...将返回 True

类似的状态（全名）：

def check_state_name(value):
  return value.lower() in statesByState

例如，

check_state_name('ALabamA')

...将返回 True