将str文本类型转换为dict

---for test---

往文件写如内容：

 1 f = open("mall.txt",'w+',encoding='utf-8')
 2 goods = {
 3     '电子产品':[
 4         ['mac',7500,7],
 5         ['iphone7',5400,5],
 6         ['thunder',7600,3]
 7     ],
 8     '母婴用品':[
 9         ['帮宝适',45.9,50],
10         ['美素佳儿',380,10]
11     ],
12     '摩托汽车':[
13         ['特斯拉',820000,2],
14         ['雷克萨斯Rx450',450000,5]
15     ],
16     '日常用品':[
17         ['东北大米',38.5,20],
18         ['上海青',3.6,47]
19     ]
20 }
21 s = str(goods)
22 f.write(s)
23 f.close()

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从文件中读取内容：

1 with open("mall.txt",'r',encoding="utf-8") as f:
2     k = f.read()
3     f.close()
4 print(k)

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如何将读取到的type为str的类dict内容转换回dict类型呢！

　　　　一、用eval函数：

1 s = eval(k)
2 
3 print(type(s))
4 for i in s:
5     print(i,s[i])

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　　　　二、用json函数：（但是必须注意的是，json格式要求的是双引号，单引号的话会报错【选中单引号 --> ctrl + shift + alt + j --> 替换单引号为双引号】）

1 print(json.loads(goods))

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　　　　　　如果是单引号报错内容：

1  print(json.loads(k))
2   File "F:Python35libjson\__init__.py", line 319, in loads
3     return _default_decoder.decode(s)
4   File "F:Python35libjsondecoder.py", line 339, in decode
5     obj, end = self.raw_decode(s, idx=_w(s, 0).end())
6   File "F:Python35libjsondecoder.py", line 355, in raw_decode
7     obj, end = self.scan_once(s, idx)
8 json.decoder.JSONDecodeError: Expecting property name enclosed in double quotes: line 1 column 2 (char 1)

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---恢复内容结束---

for test :

往文件写如内容：

 1 f = open("mall.txt",'w+',encoding='utf-8')
 2 goods = {
 3     '电子产品':[
 4         ['mac',7500,7],
 5         ['iphone7',5400,5],
 6         ['thunder',7600,3]
 7     ],
 8     '母婴用品':[
 9         ['帮宝适',45.9,50],
10         ['美素佳儿',380,10]
11     ],
12     '摩托汽车':[
13         ['特斯拉',820000,2],
14         ['雷克萨斯Rx450',450000,5]
15     ],
16     '日常用品':[
17         ['东北大米',38.5,20],
18         ['上海青',3.6,47]
19     ]
20 }
21 s = str(goods)
22 f.write(s)
23 f.close()

View Code

从文件中读取内容：

1 with open("mall.txt",'r',encoding="utf-8") as f:
2     k = f.read()
3     f.close()
4 print(k)

View Code

如何将读取到的type为str的类dict内容转换回dict类型呢！

　　　　一、用eval函数：

1 s = eval(k)
2 
3 print(type(s))
4 for i in s:
5     print(i,s[i])

View Code

　　　　二、用json函数：（但是必须注意的是，json格式要求的是双引号，单引号的话会报错【选中单引号 --> ctrl + shift + alt + j --> 替换单引号为双引号】）

1 print(json.loads(goods))

View Code

　　　　　　如果是单引号报错内容：

1  print(json.loads(k))
2   File "F:Python35libjson\__init__.py", line 319, in loads
3     return _default_decoder.decode(s)
4   File "F:Python35libjsondecoder.py", line 339, in decode
5     obj, end = self.raw_decode(s, idx=_w(s, 0).end())
6   File "F:Python35libjsondecoder.py", line 355, in raw_decode
7     obj, end = self.scan_once(s, idx)
8 json.decoder.JSONDecodeError: Expecting property name enclosed in double quotes: line 1 column 2 (char 1)

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而字典转成列表就仅仅一个items方法就可以：

> goods = {"apple":2,"ipad pro":18}
> goods.items()
dict_items([('ipad pro', 18), ('apple', 18)])