為具有相同鍵的值附加嵌套字典

Question

我已經從文件創建了一個嵌套字典，如下所示：

import csv

d = {}
with open("file.txt", 'r') as f:
    data = csv.DictReader(f, delimiter="\t")
    for row in data:
        item = d.get(row["value"], dict())
        item[row["value"]] = row["need"]
        d[row["item"]] = item

print d

但是，每個項目應有多個條目。 例如，此代碼的輸出如下所示：

d = {'key1': {'153908482': 'ctaggaacca'}, 'key2': {'115057116': 'gtaattctga'}, 'key3': {'133381371': 'ctgaaaagat'}

字典應該看起來像這樣：

d = {'key1': {'153908482': 'ctaggaacca', '143543': 'atccgatcgg'}, 'key2': {'115057116': 'gtaattctga', '12321333': 'accccgta'}, 'key3': {'133381371': 'ctgaaaagat'}

我在創建字典時丟失了一些信息。 任何幫助將不勝感激。

Answer 1

問題在於您正在將item分配給與從dict獲得的鍵不同的鍵。

item = d.get(row["value"], dict()) <-- you never assign to row["value"] so
                                       this always returns an empty dict
item[row["value"]] = row["need"]
d[row["item"]] = item              <-- since you didn't get the existing
                                       row["item"], you keep overwriting
                                       them

我對您的腳本進行了一些重新設計，使其可以與測試數據一起運行，但唯一真正的更改是從正確的密鑰中獲取數據

import csv
from cStringIO import StringIO

f = StringIO("""item    value   need
key1    153908482   ctaggaacca
key2    115057116   gtaattctga
key3    133381371   ctgaaaagat
key1    143543  atccgatcgg
key2    212321333   accccgta
""")

d = {}
#with open("file.txt", 'r') as f:

data = csv.DictReader(f, delimiter="\t")
for row in data:
#    item = d.get(row["value"], dict())
    item = d.get(row["item"], dict())
    item[row["value"]] = row["need"]
    d[row["item"]] = item

print d

這是使用defaultdict的替代實現，它為您創建內部dict

import collections
d = collections.defaultdict(dict)
data = csv.DictReader(f, delimiter="\t")
for row in data:
    d[row["item"]][row["value"]] = row["need"]
print d