在Python中迭代数值/键值对

huangapple
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英文:

Iterate on values/key pairs in Python

问题

Sure, here's the translated code part you requested:

  1. 我正在学习Python。我知道如何在JavaScript中做到这一点，但我此刻缺乏语法知识，也找不到告诉我如何做到这一点的示例。
  3. 我有以下对象数组：
  5. john_williams_compositions = [
  6.     {"year": 1973, "Title": "The Poseidon Adventure", "type": "Best Orignal Score", "status": "nominated"},
  7.     {"year": 1974, "Title": "Cinderella Liberty", "type": "Best Original Score", "status": "nominated"},
  8.     {"year": 1974, "Title": "Tom Sawyer", "type": "Best Original Score", "status": "nominated"},
  9.     {"year": 1975, "Title": "Earthquake", "type": "Best Original Score", "status": "nominated"},
  10.     {"year": 1976, "Title": "Jaws", "type": "Best Original Score", "status": "Won"},
  11.     {"year": 1978, "Title": "Close Encounters of the Third Kind", "type": "Best Original Score", "status": "nominated"},
  12.     {"year": 1978, "Title": "Star Wars: Episode IV - A New Hope", "type": "Best Original Score", "status": "Won"},
  13.     {"year": 1979, "Title": "Superman", "type": "Best Original Score", "status": "nominated"},
  14.     {"year": 1981, "Title": "Star WArs: Episode V - The Empire Strikes Back", "type": "Best Original Score", "status": "nominated"},
  15.     {"year": 1983, "Title": "E.T. the Extra Terrestrial", "type": "Best Original Score", "status": "Won"},
  16.     {"year": 1983, "Title": "If We Were in Love", "type": "Best Original Song", "status": "nominated"},
  17.     {"year": 1985, "Title": "The River", "type": "Best Original Score", "status": "nominated"},
  18.     {"year": 1988, "Title": "Empire of the Sun", "type": "Best Original Score", "status": "nominated"}
  19. ]
  21. 现在我想要获取所有状态为 "Won" 的对象并放入一个新数组中。
  23. 我自己想出了以下代码：
  25. def won(list):
  26.     result = []
  27.     for x in list:
  28.         if x.status == "Won":
  29.             result.append[i]
  30.     return result
  32. print(won(john_williams_compositions))

希望这可以帮助你！

英文:

I'm learning Python. I know how to do this in JavaScript but I lack the syntax-knowledge at this very moment nor can I find examples that tell me how to do this.

I have the following Array of Objects:

  1. john_williams_compositions = [
  2. {"year": 1973, "Title": "The Poseidon Adventure", "type": "Best Orignal Score", "status": "nominated"},
  3. {"year": 1974, "Title": "Cinderella Liberty", "type": "Best Original Score", "status": "nominated"},
  4. {"year": 1974, "Title": "Tom Sawyer", "type": "Best Original Score", "status": "nominated"},
  5. {"year": 1975, "Title": "Earthquake", "type": "Best Original Score", "status": "nominated"},
  6. {"year": 1976, "Title": "Jaws", "type": "Best Original Score", "status": "Won"},
  7. {"year": 1978, "Title": "Close Encounters of the Third Kind", "type": "Best Original Score", "status": "nominated"},
  8. {"year": 1978, "Title": "Star Wars: Episode IV - A New Hope", "type": "Best Original Score", "status": "Won"},
  9. {"year": 1979, "Title": "Superman", "type": "Best Original Score", "status": "nominated"},
  10. {"year": 1981, "Title": "Star WArs: Episode V - The Empire Strikes Back", "type": "Best Original Score", "status": "nominated"},
  11. {"year": 1983, "Title": "E.T. the Extra Terrestrial", "type": "Best Original Score", "status": "Won"},
  12. {"year": 1983, "Title": "If We Were in Love", "type": "Best Original Song", "status": "nominated"},
  13. {"year": 1985, "Title": "The River", "type": "Best Original Score", "status": "nominated"},
  14. {"year": 1988, "Title": "Empire of the Sun", "type": "Best Original Score", "status": "nominated"}
  15. ]

Now I want to get all the objects with the status "Won" in a new array.

I came up with this myself:

  1. def won(list):
  2. result = []
  3. for x in list:
  4. if x.status == "Won":
  5. result.append[i]
  6. return result
  7. print(won(john_williams_compositions))

Can anyone jumpstart me with this?

答案1

得分: 1

你可以很容易地使用列表推导来完成这个任务：

  1. def won(lst):
  2.     return [comp for comp in lst if comp['status'] == 'Won']
  4. print(won(john_williams_compositions))

或者，作为另一种选择，你可以使用filter()函数：

  1. def won(lst):
  2.     return list(filter(lambda comp: comp['status'] == 'Won', lst))
  4. print(won(john_williams_compositions))
英文:

You can do this very easily with a list comprehension:

  1. def won(lst):
  2. return [comp for comp in lst if comp['status'] == 'Won']
  3. print(won(john_williams_compositions))

Or, alternatively, you can use the filter() function:

  1. def won(lst):
  2. return list(filter(lambda comp: comp['status'] == 'Won', lst))
  3. print(won(john_williams_compositions))

答案2

得分: 1

你只需要迭代列表（字典列表），然后选择其中status键等于Won的部分。

最好编写一个处理任何状态值的函数，类似这样：

  1. john_williams_compositions = [
  2.     {"year": 1973, "Title": "The Poseidon Adventure", "type": "Best Orignal Score", "status": "nominated"},
  3.     {"year": 1974, "Title": "Cinderella Liberty", "type": "Best Original Score", "status": "nominated"},
  4.     {"year": 1974, "Title": "Tom Sawyer", "type": "Best Original Score", "status": "nominated"},
  5.     {"year": 1975, "Title": "Earthquake", "type": "Best Original Score", "status": "nominated"},
  6.     {"year": 1976, "Title": "Jaws", "type": "Best Original Score", "status": "Won"},
  7.     {"year": 1978, "Title": "Close Encounters of the Third Kind", "type": "Best Original Score", "status": "nominated"},
  8.     {"year": 1978, "Title": "Star Wars: Episode IV - A New Hope", "type": "Best Original Score", "status": "Won"},
  9.     {"year": 1979, "Title": "Superman", "type": "Best Original Score", "status": "nominated"},
  10.     {"year": 1981, "Title": "Star WArs: Episode V - The Empire Strikes Back", "type": "Best Original Score", "status": "nominated"},
  11.     {"year": 1983, "Title": "E.T. the Extra Terrestrial", "type": "Best Original Score", "status": "Won"},
  12.     {"year": 1983, "Title": "If We Were in Love", "type": "Best Original Song", "status": "nominated"},
  13.     {"year": 1985, "Title": "The River", "type": "Best Original Score", "status": "nominated"},
  14.     {"year": 1988, "Title": "Empire of the Sun", "type": "Best Original Score", "status": "nominated"}
  15. ]
  17. def get_by_status(lst, status):
  18.     result = []
  20.     for d in lst:
  21.         if d.get('status') == status:
  22.             result.append(d)
  23.             
  24.     return result
  26. print(get_by_status(john_williams_compositions, 'Won'))

输出：

  1. {'year': 1976, 'Title': 'Jaws', 'type': 'Best Original Score', 'status': 'Won'}, {'year': 1978, 'Title': 'Star Wars: Episode IV - A New Hope', 'type': 'Best Original Score', 'status': 'Won'}, {'year': 1983, 'Title': 'E.T. the Extra Terrestrial', 'type': 'Best Original Score', 'status': 'Won'}]

注意： get_by_status() 可以以一行代码的形式作为列表推导式来实现。因为显然是初学者，所以以这种方式编写以提高清晰度。

  1. def get_by_status(lst, status):
  2.     return [d for d in lst if d.get('status') == status]
英文:

You just need to iterate over the list (of dictionaries) then select those where the status key is equal to Won.

Probably best to write a function that will handle any status value. Something like this:

  1. john_williams_compositions = [
  2.     {"year": 1973, "Title": "The Poseidon Adventure", "type": "Best Orignal Score", "status": "nominated"},
  3.     {"year": 1974, "Title": "Cinderella Liberty", "type": "Best Original Score", "status": "nominated"},
  4.     {"year": 1974, "Title": "Tom Sawyer", "type": "Best Original Score", "status": "nominated"},
  5.     {"year": 1975, "Title": "Earthquake", "type": "Best Original Score", "status": "nominated"},
  6.     {"year": 1976, "Title": "Jaws", "type": "Best Original Score", "status": "Won"},
  7.     {"year": 1978, "Title": "Close Encounters of the Third Kind", "type": "Best Original Score", "status": "nominated"},
  8.     {"year": 1978, "Title": "Star Wars: Episode IV - A New Hope", "type": "Best Original Score", "status": "Won"},
  9.     {"year": 1979, "Title": "Superman", "type": "Best Original Score", "status": "nominated"},
  10.     {"year": 1981, "Title": "Star WArs: Episode V - The Empire Strikes Back", "type": "Best Original Score", "status": "nominated"},
  11.     {"year": 1983, "Title": "E.T. the Extra Terrestrial", "type": "Best Original Score", "status": "Won"},
  12.     {"year": 1983, "Title": "If We Were in Love", "type": "Best Original Song", "status": "nominated"},
  13.     {"year": 1985, "Title": "The River", "type": "Best Original Score", "status": "nominated"},
  14.     {"year": 1988, "Title": "Empire of the Sun", "type": "Best Original Score", "status": "nominated"}
  15.     ]
  17. def get_by_status(lst, status):
  18.     result = []
  20.     for d in lst:
  21.         if d.get('status') == status:
  22.             result.append(d)
  23.             
  24.     return result
  26. print(get_by_status(john_williams_compositions, 'Won'))

Output:

  1. {'year': 1976, 'Title': 'Jaws', 'type': 'Best Original Score', 'status': 'Won'}, {'year': 1978, 'Title': 'Star Wars: Episode IV - A New Hope', 'type': 'Best Original Score', 'status': 'Won'}, {'year': 1983, 'Title': 'E.T. the Extra Terrestrial', 'type': 'Best Original Score', 'status': 'Won'}]

Note: get_by_status() could be implemented as a list comprehension in one line of code. As OP is obviously a beginner, it's written this way for clarity.

  1. def get_by_status(lst, status):
  2. return [d for d in lst if d.get('status') == status]

答案3

得分: 1

这是一个简单的实现示例，因为你是初学者，列表推导可能看起来不太容易理解：

  1. def won(list):
  2.     result = []
  3.     for x in list:
  4.         if x['status'] == 'Won':
  5.             print(x['status'])
  6.             result.append(x)
  7.     return result
  9. print(won(john_williams_compositions))
英文:

Since you are a beginner and list comprehension might not look very sraightforward to you, here is a simple implementation:

  1. def won(list):
  2. result = []
  3. for x in list:
  4. if x['status'] == 'Won':
  5. print(x['status'])
  6. result.append(x)
  7. return result
  8. print(won(john_williams_compositions))

答案4

得分: 1

x 是一个 dict。与 JavaScript 不同，访问 dict 中给定键的值和访问属性值之间存在语法差异。

x["foo"] # 与键 "foo" 关联的值
x.foo # 与属性 "foo" 关联的值

你的循环需要使用前者：

  1. def won(list):
  2.     result = []
  3.     for x in list:
  4.         if x["status"] == "Won":
  5.             result.append(x)
  6.     return result
英文:

x is a dict. Unlike Javascript (I gather), there is a syntactic difference between access the value for a given key in a dict and accessing the value of an attribute.

  1. x["foo"]  # Value associated with key "foo"
  2. x.foo  # Value associated with the attribute "foo"

Your loop requires the former:

  1. def won(list):
  2. result = []
  3. for x in list:
  4. if x["status"] == "Won":
  5. result.append[i]
  6. return result

huangapple
  • 本文由 发表于 2023年5月20日 22:37:22
  • 转载请务必保留本文链接：https://go.coder-hub.com/76295754.html
  • arrays
  • python
  • python-re
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