Question

我有一本字典

{0: 12, 1: 1, 2: 13, 3: 7, 4: 0}

我想找到值大于0的最高字典键。

在这种情况下，答案是3。

最好的方法是什么？

Answer 1

使用genexpr过滤掉＆＃34;坏＆＃34;值和max保持最高值：

# On Py2, use .iteritems() instead of .items()
max(k for k, v in mydict.items() if v > 0)

或者，如果在没有引发异常的情况下没有键符合条件，则需要有默认值：

# Py3 max has default, which makes this super-easy:
max((k for k, v in mydict.items() if v > 0), default=SOMEVALUEGOESHERE)

# Py2 doesn't have default; workaround is to catch exception and use a default (EAFP):
try:
    mymax = max(k for k, v in mydict.iteritems() if v > 0)
except ValueError:
    mymax = SOMEVALUEGOESHERE

# Or if you can't do that for some reason, make a listcomp instead of genexpr
# and check for at least one surviving key before calling max (LBYL)
goodkeys = [k for k, v in mydict.iteritems() if v > 0]
mymax = max(goodkeys) if goodkeys else SOMEVALUEGOESHERE

Answer 2

您可以使用max和dict.items()执行此操作：

d = {0: 12, 1: 1, 2: 13, 3: 7, 4: 0}

highest = max(i for i,j in d.items() if j > 0)

Python - 找到值大于零的最高字典键

2 个答案: