我有一個列表python-多維列表，並創建一個字典，並計算其平均

這樣

myList = [ ['jan','423','523','645'], 
      ['jan','654','754','765'], 
      ['nov','756','087','140'], 
      ['nov','233','123','032'] 
      ['apr','654','786','223'] ]

我想通過列表和羣組的所有基於子列表（myList中的）第一個元素（即'jan'，'nov'）在字典中。其關鍵也是列表的第一個元素。

myDict = {'jan':[ 
       ['423','654'], # average 
       ['523','754'], # average 
       ['645','765'] # average 
       ], 
     'nov':[ 
       ['756','233'], # average 
       ['087','123'], # average 
       ['140','032'] # average 
       ], 
     'apr':[ 
       ['654'], # average 
       ['786'], # average 
       ['223'] # average 
       ], 
     }

然後我想計算該字典的所有列表元素的平均值。

這樣

myDict = {'jan':[ 
       ['423','654'], # average 
       ['523','754'], # average 
       ['645','765'] # average 
       ],.....

注意：這僅僅是樣本數據，我有數百elemnts的像子列表[34,654,756,8,675,75,64,3,45，... .n]，[sublist-2..n]，[sublist-3 .... n]] ，但每個子列表的長度是固定的。

mycode的：

myList 
db = {}  
for i in myList: 

    human = i[0]  
    newlist = i[1:] 

    # print pprint(db) 
    columns = [] 
    counter = 0 

    while counter < len(newlist): 
     if db.has_key(human): 
      db[human][counter].append(newlist[counter]) 
     else: 
      columns.append([newlist[counter]]) 
      db[human] = columns 
     counter += 1

下面列出的代碼工作良好，當我只有2項。

human = i[0] 
col_1 = i[1] 
col_2 = i[2] 

if db.has_key(human): 
    db[human][0].append(col_1) 
    db[human][1].append(col_2) 
else: 
    db[human] = [ [col_1], [col_2] ] 

print 
pprint(db) 
print columns 

# function to calculate average 
def getAvg(column): 
    total = 0 
    average = 0 
    for val in column: 
     length = len(column) 
     int_val = float(val) 
     total += int_val 
     average = total/length 
    return average 

col_1_avg = getAvg(col_1) 
col_2_avg = getAvg(col_2) 

result = human + ',' + str(getAvg(col_1)) + ',' +str(getAvg(col_2))

來源

2014-02-10 ArrC

看http://stackoverflow.com/questions/21674331/group-by-multiple-keys-and-summarize-average-values-of-a-list-of-dictionaries/21674941 ＃21674941 –

請不要使用'dict.has_key'來檢查密鑰的存在，它已被棄用。在my_dict中使用'if k：...' –

myList = [['jan','423','523','645'], 
      ['jan','654','754','765'], 
       ['nov','756','087','140'], 
       ['nov','233','123','032'], 
       ['apr','654','786','223']] 

from collections import defaultdict 
mydict = defaultdict(list) 
for each in myList: 
    mydict[each[0]].append(each[1:]) 
datadict = {} 
for each in mydict: 
    datadict[each] = zip(*mydict[each]) 
print datadict

來源

2014-02-10 13:04:59

python-多維列表，並創建一個字典，並計算其平均

下面列出的代碼工作良好，當我只有2項。

回答

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