按每個子列表中的某些值對子列表分組列表

Question

我有一個包含列表的字典。例如，

{1: [[sender11, receiver11, text11, address11]], 
2: [[sender21, receiver21, text21, address21], [sender22, receiver22, text22, address22]], 
3: [[sender31, receiver31, text31, address31], [sender32, receiver32, text32, address32], [sender33, receiver33, text33, address33]] 
4: [[sender41, receiver41, text41, address41], [sender42, receiver42, text42, address42], [sender43, receiver43, text43, address43], [sender44, receiver44, text44, address44]]} 

我想要做的是，對於那些包含有2個或多個元素（即dict[2]，在這個例子中dict[3]和dict[4]）的列表字典元素，我做的sender, receiver, text的每一個的比較列表值。對於每組列表值相同的sender, receiver, text，我會做一些事情。

因此，例如，在dict[3]，如果sender31, receiver31, text31如sender32, receiver32, text32和sender33, receiver33, text33相同的值，然後我會做所有的3個列表值的東西。

說，在dict[4]，如果sender41, receiver41, text41是相同的值sender42, receiver42, text42，而sender43, receiver43, text43來自sender41, receiver41, text41相同的值sender44, receiver44, text44，但不同的，然後我會在這2組獨立工作。

我寫了一個Python腳本，幾乎蠻力比較的sender21, receiver21, text21和sender22, receiver22, text22的值，即

if sender21 == sender22 and receiver21 == receiver22 and text21 == text22: 
    # Do something 

這是不是有效，因爲它僅適用於2個列表值，但我不知道我應該如何實現這使得它適用於任何號碼錶的值大於1

Answer 1

我覺得defaultdict是去這裏明顯的方式：

from collections import defaultdict 

def collate(seq): 
    groups = defaultdict(list) 
    for subseq in seq: 
     groups[tuple(subseq[:3])].append(subseq[3]) 
    return groups 

根據您的實際數據，您可能會用上述功能替換上述功能中的tuple(subseq[:3])。 (subseq[1], subseq[4], subseq[5])，或附加subseq[3]與subseq本身......這將取決於你在做什麼與數據。

但是，鍵必須是元組而不是列表，因爲鍵必須是不可變的。

例子：

>>> data = [ 
...  ['S1', 'R1', 'T1', 'A3'], 
...  ['S2', 'R2', 'T2', 'A4'], 
...  ['S1', 'R1', 'T1', 'A5'], 
...  ['S2', 'R2', 'T2', 'A6'] 
... ] 

>>> collate(data) 
defaultdict(<type 'list'>, { 
    ('S2', 'R2', 'T2'): ['A4', 'A6'], 
    ('S1', 'R1', 'T1'): ['A3', 'A5'] 
}) 

你可以用這個工作就像你的任何其他詞典，例如

>>> for (sender, receiver, text), addresses in collate(data).items(): 
...  print sender, receiver, text 
...  print '|'.join(addresses) 
...  print 
... 
S2 R2 T2 
A4|A6 

S1 R1 T1 
A3|A5