如何在 Python 中从文件创建字典，其中值是一个列表

Question

我有一个 txt 文件，我想将值读入字典。与普通字典不同，每个key的值是一个值对，例如：

tiger eat meat
tiger eat people
rabbit eat carrot
people can walk
trees has root
people has hand

我想要一本字典，

tiger, {eat, meat}, {eat, people}
rabbit, {eat, carrot}
trees, {has, root}
people, {can, walk}, {has, hand}

我应该只将read lines、split(\n) 分成 3 个项目并将第一个作为键存储，其余两个作为值存储吗？还是有更好的方法来存储这两个值？

我的目标是，当我查询老虎吃什么时，我想得到答案meat 和people。

Answer 1

创建一个字典，其键是主题，其值是一个列表，其中包含以动词为键、对象为值的字典（见结果）。

animal_attr = {} #Don't mind the name :)
with open (filename,"r") as f:
    for line in f:
        items = line.split()
        if items[0] not in animal_attr.keys():
            animal_attr[items[0]] = []            
        animal_attr[items[0]].append({items[1]: items[2]})

print(animal_attr)
#{'tiger': [{'eat': 'meat'}, {'eat': 'people'}], 'trees': [{'has': 'root'}],
# 'rabbit': [{'eat': 'carrot'}], 'people': [{'can': 'walk'}, {'has': 'hand'}]}

Answer 2

import collections

lines=[]
with open('data1', 'r') as f:
    lines=list(map(lambda line:line.strip(), f.readlines()))

d, flag=collections.defaultdict(list), False
for line in lines:
    temp=list(map(lambda x:x.strip(), line.split()))
    d[temp[0]].append(temp[1:])
print(d)

这是输出：

$ cat data1
tiger eat meat
tiger eat people
rabbit eat carrot
people can walk
trees has root
people has hand
$ python3 a.py 
defaultdict(<class 'list'>, {'rabbit': [['eat', 'carrot']], 'trees': [['has', 'root']], 'tiger': [['eat', 'meat'], ['eat', 'people']], 'people': [['can', 'walk'], ['has', 'hand']]})

如果你想要这个结构：

$ python3 a.py 
defaultdict(<class 'list'>, {'people': [{'can': 'walk'}, {'has': 'hand'}], 'tiger': [{'eat': 'meat'}, {'eat': 'people'}], 'trees': [{'has': 'root'}], 'rabbit': [{'eat': 'carrot'}]})

将脚本中的倒数第二行替换为：

d[temp[0]].append({temp[1]:temp[2]})

Answer 3

import collections

d=collections.defaultdict(list)
with open('text.txt', 'r') as lines:
    for line in lines:
        temp=line.split()
        d[temp[0]].append({temp[1]: temp[2]})
print(d)

输出：

defaultdict(<type 'list'>, {'tiger': [{'eat': 'meat'}, {'eat': 'people'}], 'trees': [{'has': 'root'}], 'rabbit': [{'eat': 'carrot'}], 'people': [{'can': 'walk'}, {'has': 'hand'}]})

Answer 4

首先，你可以根据主语和动词来积累数据，像这样

data = {}
with open("Input.txt") as fin:
    for line in fin:
        subject, verb, obj = line.strip().split()
        data.setdefault(subject, {}).setdefault(verb, []).append(obj)

现在，data 将如下所示

{'people': {'can': ['walk'], 'has': ['hand']},
 'rabbit': {'eat': ['carrot']},
 'tiger': {'eat': ['meat', 'people']},
 'trees': {'has': ['root']}}

我们基本上已经创建了将值作为列表的嵌套字典。

现在，只需以您喜欢的方式迭代和打印结果即可

for subject in data:
    print subject,
    for verb in data[subject]:
        for obj in data[subject][verb]:
            print "{{{}, {}}}".format(verb, obj),
    print

输出

tiger {eat, meat} {eat, people}
trees {has, root}
rabbit {eat, carrot}
people {has, hand} {can, walk}

---

注意：如果数据的原始顺序很重要，那么可以使用collections.OrderedDict代替普通字典，像这样

from collections import OrderedDict


data = OrderedDict()
with open("Input.txt") as fin:
    for line in fin:
        subject, verb, obj = line.strip().split()
        data.setdefault(subject, OrderedDict()).setdefault(verb, []).append(obj)

Answer 5

一旦您从文件中读取了这些行，您就可以为此创建一个nested defaultdict：

d = defaultdict(lambda: defaultdict(list))

for line in lines:
    words = line.split()
    d[words[0]][words[1]].append(words[2])

如果您print(d)，您将获得以下信息：

defaultdict(<function <lambda> at 0x7fa858444320>, {'tiger': defaultdict(<type 'list'>, {'eat': ['meat', 'people'], 'eats': []}), 'trees': defaultdict(<type 'list'>, {'has': ['root']}), 'rabbit': defaultdict(<type 'list'>, {'eat': ['carrot']}), 'people': defaultdict(<type 'list'>, {'has': ['hand'], 'can': ['walk']})})

而且，您可以通过以下方式访问老虎吃什么：

>>> d['tiger']['eat']
['meat', 'people']

如果你想看看people 能做什么：

>>> d['people']['can']
['walk']