[英]Python/Pygame colours are no tuples: unhashable type error when used as dictionary keys
[英]Referencing to elements of tuples when used as keys in a python dictionary
假設我有這本字典:
dic = {('a','b'): 0, ('b','c'): 1, ('d','e'): 2}
如何引用密鑰中的元素? 例如,如果程序在鍵的第二個元素中找到字符“ c”,我希望程序執行特定行。
您可以簡單地遍歷鍵並檢查以下內容:
>>> dic = {('a','b'): 0, ('b','c'): 1, ('d','e'): 2}
>>> for key, value in dic.items():
... if key[1] == 'c':
... print key, value # or do something else
...
('b', 'c') 1
使用列表理解:
>>> dic = {('a','b'): 0, ('b','c'): 1, ('d','e'): 2}
>>> lines =[dic[k] for k in dic if k[1]=='c'] #returns all matching items
>>> lines
[1]
對於鍵值對,迭代dict.iteritems
:
>>> [(k, v) for k, v in dic.iteritems() if k[1]=='c']
[(('b', 'c'), 1)]
如果有多條這樣的行,而您只有一條,則使用next
:
>>> next((dic[k] for k in dic if k[1]=='c'), None)
1
您可以通過遍歷keys()
來解包所有鍵的第一和第二個元素
dic = {('a','b'): 0, ('b','c'): 1, ('d','e'): 2}
for first, second in dic.keys():
if second == 'c':
# execute the line you want
pass
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