迭代有序字典导致：'float' 对象没有属性 'items'

Question

我有以下打印有序字典的函数：

def printSQN(analyzer):
    sqn = round(analyzer.sqn, 2)
    print(f'The System Quality Number (SQN) is: {sqn}')

输出如下所示：

OrderedDict([('sharperatio', 0.19697863771541763)])

我想要'unpack'这个有序的字典并且只打印出值0.19697863771541763.

为此，我尝试了以下方法：

def printSQN(analyzer):
    sqn = round(analyzer.sqn, 2)
    for key, value in sqn.items():
        print(f'The System Quality Number (SQN) is: {value}')

但是，运行上面的代码会导致以下错误：

Traceback (most recent call last):
  File "backtest_02a.py", line 100, in <module>
    printSQN(the_strategy.analyzers.sqn.get_analysis())
  File "backtest_02a.py", line 50, in printSQN
    for key, value in sqn.items():
AttributeError: 'float' object has no attribute 'items'

Backtrader 库中的文档说：

"The Analyzer base class creates a self.rets (of type collections.OrderedDict) member attribute to return the analysis. This is done in the method create_analysis which can be overriden by subclasses if creating custom analyzers."

看来我的方法是文档中建议的方法：https://docs.python.org/3/library/stdtypes.html#dict.items

有人看到我的 for loop 哪里有问题吗？提前致谢！

Answer 1

以下解决方案有效：

list(the_strategy.analyzers._sharpe.get_analysis().values())[0]

迭代有序字典导致：'float' 对象没有属性 'items'

Iterating on an Ordered Dictionary results in: 'float' object has no attribute 'items'

python

for-loop

ordereddictionary