如何在Python中初始化多維數組？

Question

我很抱歉，如果這是一個重複的問題，但我找不到任何類似的例子，所以尋求你的幫助。

lookup = {} 

# These values will be filled by DB lookup service at runtime 
# Maximum array length for category is unknown before program start 
# Format [Lookup Category], [Lookup Key], Lookup Id 

lookup['name']['John'] = 1 
lookup['name']['Jane'] = 2 
lookup['name']['Joe'] = 3 
lookup['gender']['Male'] = 1 
lookup['gender']['Female'] = 2 
lookup['country']['Japan'] = "jp" 
lookup['country']['China'] = "ch" 

print lookup['name']['Jane'] 
print lookup['gender']['Female'] 
print lookup['country']['China'] 

Answer 1

你可能想collections.defaultdict

例如

from collections import defaultdict 

lookup = defaultdict(dict) 
lookup['name']['John'] = 1 
lookup['name']['Jane'] = 2 
lookup['name']['Joe'] = 3 
lookup['gender']['Male'] = 1 
lookup['gender']['Female'] = 2 
lookup['country']['Japan'] = "jp" 
lookup['country']['China'] = "ch" 

print lookup['name']['Jane'] 
print lookup['gender']['Female'] 
print lookup['country']['China']