Python json /字典問題

Question

我最近開始使用python進行json讀寫，並且不得不從提供的json文件中將一些書籍實施到圖書館系統中，看起來像這樣；

[
  {
    "author": "Chinua Achebe",
    "country": "Nigeria",
    "imageLink": "images/things-fall-apart.jpg",
    "language": "English",
    "link": "https://en.wikipedia.org/wiki/Things_Fall_Apart\n",
    "pages": 209,
    "title": "Things Fall Apart",
    "year": 1958
  },

我編寫了這小段代碼，將我的書放入python字典中，然后將其實現到更大的系統中。

import json

with open('C:/Users/daann/Downloads/booksset1.json') as json_file:

    booklist = json.load(json_file)

print(booklist)

我的問題是關於字典，以及如何從字典中的json讀取數據，現在我的數據在一個長字典中，但是如何讀取（例如，僅作者）？ 還是只有名字？ 我完全忘記了，在任何地方都找不到。

另一個問題，如果我想拿出來，例如我在這里放的第一本書，作者叫“ Chinua Achebe”，有沒有辦法做到這一點（拿出與該書有關的所有數據，具有給定的作者姓名）？

Answer 1

在每個條目booklist是一個Python字典，簡稱dict 。 訪問字典中的字段使用方式book[field_name] 。 在您的情況下， field_name的值為"author" 。

for book in booklist:
    print(book["author"]) # or any field you want

Answer 2

以下是一些遍歷數據的方法：

booklist = [
  {
    "author": "Chinua Achebe",
    "country": "Nigeria",
    "imageLink": "images/things-fall-apart.jpg",
    "language": "English",
    "link": "https://en.wikipedia.org/wiki/Things_Fall_Apart\n",
    "pages": 209,
    "title": "Things Fall Apart",
    "year": 1958
  },

   {
    "author": "Joe Jackson",
    "country": "USA",
    "imageLink": "images/white_socks.jpg",
    "language": "English",
    "link": "https://en.wikipedia.org/wiki/white_sox",
    "pages": 500,
    "title": "My Shoes Hurt My Feet",
    "year": 1919
  },

    {
    "author": "Jane Mae",
    "country": "Canada",
    "imageLink": "images/ehhhh.jpg",
    "language": "French",
    "link": "https://en.wikipedia.org/wiki/ehhhh\n",
    "pages": 123,
    "title": "What's That Aboot",
    "year": 2000
  }]


# Get all authors in a list (might want to convert to set to remove duplicates)     
authors = [d["author"] for d in booklist] 
print (authors) 

# Find all books by author 'Chinua Achebe'
for book in booklist:
    if book['author'] == 'Chinua Achebe':
        print (book)


# Find all books later than year 1950         
for book in booklist:
    if book['year'] > 1950:
        print (book['title'], book['year'])

Answer 3

如果要按作者獲取書籍，則需要構建另一個查找作者->書籍：

import collections
books_by_author = collections.defaultdict(list)
for b in booklist:
    books_by_author[d['author']].append(b)

# and then
books_by_Chinua_Achebe = books_by_author['Chinua Achebe']

此鏈接對於以字典開頭可能會有所幫助： https : //realpython.com/python-dicts/