將str文本類型轉換爲dict

---for test---

1. 往文件寫如內容：

    1 f = open("mall.txt",'w+',encoding='utf-8')
    2 goods = {
    3     '電子產品':[
    4         ['mac',7500,7],
    5         ['iphone7',5400,5],
    6         ['thunder',7600,3]
    7     ],
    8     '母嬰用品':[
    9         ['幫寶適',45.9,50],
   10         ['美素佳兒',380,10]
   11     ],
   12     '摩托汽車':[
   13         ['特斯拉',820000,2],
   14         ['雷克薩斯Rx450',450000,5]
   15     ],
   16     '平常用品':[
   17         ['東北大米',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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2. 從文件中讀取內容：

   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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3. 如何將讀取到的type爲str的類dict內容轉換回dict類型呢！

　　　　1、用eval函數：

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

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　　　　2、用json函數：（可是必須注意的是，json格式要求的是雙引號，單引號的話會報錯【選中單引號 --> ctrl + shift + alt + j  --> 替換單引號爲雙引號】）

　　　　　　

1 print(json.loads(goods))

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　　　　　　若是是單引號報錯內容：

1  print(json.loads(k))
2   File "F:\Python35\lib\json\__init__.py", line 319, in loads
3     return _default_decoder.decode(s)
4   File "F:\Python35\lib\json\decoder.py", line 339, in decode
5     obj, end = self.raw_decode(s, idx=_w(s, 0).end())
6   File "F:\Python35\lib\json\decoder.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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---恢復內容結束---

for test :

1. 往文件寫如內容：

    1 f = open("mall.txt",'w+',encoding='utf-8')
    2 goods = {
    3     '電子產品':[
    4         ['mac',7500,7],
    5         ['iphone7',5400,5],
    6         ['thunder',7600,3]
    7     ],
    8     '母嬰用品':[
    9         ['幫寶適',45.9,50],
   10         ['美素佳兒',380,10]
   11     ],
   12     '摩托汽車':[
   13         ['特斯拉',820000,2],
   14         ['雷克薩斯Rx450',450000,5]
   15     ],
   16     '平常用品':[
   17         ['東北大米',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

    

2. 從文件中讀取內容：

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

   View Code

    

3. 如何將讀取到的type爲str的類dict內容轉換回dict類型呢！

　　　　1、用eval函數：

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

View Code

　　　　2、用json函數：（可是必須注意的是，json格式要求的是雙引號，單引號的話會報錯【選中單引號 --> ctrl + shift + alt + j  --> 替換單引號爲雙引號】）

　　　　　　

1 print(json.loads(goods))

View Code

　　　　　　若是是單引號報錯內容：

1  print(json.loads(k))
2   File "F:\Python35\lib\json\__init__.py", line 319, in loads
3     return _default_decoder.decode(s)
4   File "F:\Python35\lib\json\decoder.py", line 339, in decode
5     obj, end = self.raw_decode(s, idx=_w(s, 0).end())
6   File "F:\Python35\lib\json\decoder.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)

View Code

 

---

而字典轉成列表就僅僅一個items方法就能夠：

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