Question

in ruby：

hash = {'a' => {'abs' => 1}, 'b' => {'abs' => 4}, 'abc' => {'abs' => 6}}

DONT_COUNT_KEYS = ['abc']
sum = 0
hash.collect {|key,value| sum += value['abs'] unless DONT_COUNT_KEYS.include?(key)}
=> [1, 5, nil]
irb(main):007:0> sum
=> 5

我想在一行中在python中做同样的事情。我有什么选择？ each不适用于字典而values()不适用于lambda

Answer 1

您可以在sum中使用生成器表达式来执行此操作

>>> h = {'a': {'abs':1},
         'b': {'abs':4},
         'c': {'abs':6},
         'd': {'abs':7},
         'e': {'abs':3}}
>>> DONT_COUNT_KEYS = 'abc'
>>> sum(value['abs'] for key, value in h.items() if key not in DONT_COUNT_KEYS)
10

Answer 2

for key, value in hash.items():
    sm += value['abs'] if key not in DONT_COUNT_KEYS else 0

或列表理解

[sm += value['abs'] for key, value in hash.items() if key not in DONT_COUNT_KEYS]

如何从python中的字典中收集

2 个答案: