[英]pythonic way of initialization of dict in a for loop
有沒有python初始化字典的方法?
animals = ["dog","cat","cow"]
for x in animals:
primers_pos[x]={}
有沒有像
(primers_pos[x]={} for x in animals)
您可以使用字典理解功能(Python 2.7+支持):
>>> animals = ["dog", "cat", "cow"]
>>> {x: {} for x in animals}
{'dog': {}, 'cow': {}, 'cat': {}}
您也可以使用collections.defaultdict
primer_pos = defaultdict(dict)
然后,每當您使用新密鑰引用primer_pos時,都會自動創建一個字典
primer_pos['cat']['Fluffy'] = 'Nice kitty'
將通過鏈式創建{'Fluffy':'Nice Kitty'}作為字典“ primary_pos ”中關鍵字“ cat”的值
hash = {data: True for data in ['a', 'b', 'c']}
print(hash)
輸出:{'a':真,'b':真,'c':真}
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