Question

def printdash():
    print('-' * 10)


# creates a mapping of state to abbreviation
states = {
'Oregon': 'OR',
'Florida': 'FL',
'California': 'CA',
'New York': 'NY',
'Michigan': 'MI'
}

# creates a basic set of states with some cities in them

cities = {
'CA': 'Sacramento',
'MI': 'Lansing', 
'FL': 'Tallahasee'}

# add some more cities to the list
cities['NY'] = 'Albany'
cities['OR'] = 'Eugene'

# Print out some cities
printdash()
print('New York State has: ', cities['NY'])
print('Oregon has: ', cities['OR'])

# print some states
printdash()
print 'Michigan\'s abbreviation is: ' , states['Michigan']
print 'Florida\'s abbreviation is: ', states['Florida']

# do it by using the state then cities dict. Nested dicts!
printdash()
print 'Michigan has: ', cities[states['Michigan']]
print 'Florifa has: ', cities[states['Florida']] 

# print every states abbreviation
printdash()
for states, abbrev in states.items():
    print '%s is abbreviated as %s' % (states, abbrev)
# end

# print every city in each state
printdash()
for abbrev, cities in cities.items():
    print '%s has the city %s' % (abbrev, cities)
# end

# doing both at the same time
printdash()
for state, abbrev in states.items():
    print '%s state is abbreviated %s and has city %s' % (state, abbrev,  cities[abbrev])

每次运行它都会到达第54行（最后一个for循环），然后引发属性错误标志。对于我的生活，我无法弄清楚我做错了什么作为另外两个循环，在大多数相同的时尚工作中没有问题。

在这个网站上查找其他解决方案，我发现这些例子比我能理解的要复杂得多，而且解决方案似乎比这个非常普遍的情况更具体。

克斯！

Answer 1

当您在第一个循环中指定states作为目标时，您会将states的名称重新指定给states.items()元组的第一个项目。

这是您正在做的简化版本：

>>> i = "hello"
>>> for i in range(2): print i
... 
0
1
>>> i
1

如您所见，i是循环后的int而非str，其引用的值已更改。

作为解决方案，只需将循环中的states重命名为其他内容，例如state或tmp_states。所以：

for state, abbrev in states.items():
    print '%s is abbreviated as %s' % (state, abbrev)

另外对存在相同模式的其他循环执行相同操作，例如for abbrev, cities in cities.items(): - ＆gt; for abbrev, city in cities.items()。

Answer 2

该行

for states, abbrev in states.items():
    print('%s is abbreviated as %s' % (states, abbrev))

造成麻烦。

由于python中循环变量的范围不仅限于循环（你可以说，它们会泄漏到你的程序中），所以此行states之后将是一个字符串。< / p>

您可以通过运行

来调试它

print(states)
for states, abbrev in states.items():
    print('%s is abbreviated as %s' % (states, abbrev))
print(states)

将打印

----------
{'California': 'CA', 'Michigan': 'MI', 'New York': 'NY', 'Florida': 'FL', 'Oregon': 'OR'}
California is abbreviated as CA
Michigan is abbreviated as MI
New York is abbreviated as NY
Florida is abbreviated as FL
Oregon is abbreviated as OR
Oregon

此外，您应该检查您对print的使用情况。请坚持使用一个版本的print语句，print 'foo' 或 print('foo')。第二种用法（作为函数）是唯一可以在Python 3.X中使用的用法。

Answer 3

'city'和'states'都被第一个和第二个for循环覆盖。使用不同的变量名称应该修复它。

AttributeError：'str'对象在循环

3 个答案: