Question

我已经从文件中创建了一个嵌套字典：

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，每个项目应该有多个条目。例如，以下是此代码的输出结果：

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

字典看起来应该是这样的：

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

我在创建字典时丢失了一些信息。任何帮助将不胜感激。

Answer 1

问题在于您将item分配给与从词典获得的密钥不同的密钥。

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

我稍微重写了你的脚本，以便它可以使用测试数据运行，但唯一真正的改变是从正确的密钥中获取数据

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

这是使用defaultdict的替代实现，它为您创建内部字典

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

为具有相同键的值附加嵌套字典

1 个答案: