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python - Dictionary Inception - 如何打印示例

问题描述

试图访问字典里面的键值，里面，字典，里面的字典。这应该打印：“在法国巴黎，您访问了 Resturaunt 1、5 次。” 我怎样才能解决这个问题？

travel_log = {
  "France": {
    "cities_visited": {
      "Paris": { 
        "resturaunt": "Resturaunt 1", 
        "total_visits": 5,
      }, 
      "Lille": {
        "resturaunt": "Resturaunt 2", 
        "total_visits": 2,
      },
      "Dijon": {
        "resturaunt": "Resturaunt 3", 
        "total_visits": 3,
      }
    },
  },
}

#Example Should print:
# In Paris, France you visited Resturaunt 1, 5 times.
for country in travel_log: 
  for city in travel_log[country]: # for Paris in France in Travel_log
    print(f"In {travel_log[country][city]}, {travel_log[country]} you visted {travel_log[country][city][resturaunt]}, {travel_log[country][city][total_visits]} times.")

标签： python

解决方案

在您的代码中更改以下内容：

  1. 从：

    for city in travel_log[country]:  # This will give you ["cities_visited"]

    至：

    for city in travel_log[country]["cities_visited"]:  # This will give you ["Paris", "Lille", Dijon]

    • 您缺少cities_visited字典键。流程应该是：

      • travel_log -> 国家 -> city_visited -> 城市 -> 餐厅
      • travel_log -> 国家 -> city_visited -> 城市 -> total_visits

  2. 从：

    print(f"In {travel_log[country][city]}, {travel_log[country]} you visited {travel_log[country][city][restaurant]}, {travel_log[country][city][total_visits]} times.")

    至：

    print(f"In {city}, {country} you visited {travel_log[country]['cities_visited'][city]['restaurant']}, {travel_log[country]['cities_visited'][city]['total_visits']} times.")
    • 如果您只想要国家或城市名称，请不要访问travel_log[country]nor travel_log[country]['cities_visited'][city]，这些语句转换为访问 和 的值，travel_log['France']它们travel_log['France']['cities_visited']['Paris']都会为您提供它们的字典值，例如 {"restaurant": "Restaurant 1", "total_visits": 5}，但不是 country"France"和 city的实际字符串值"Paris"。实际上，您想要的值已经在变量country和city.
    • 当您尝试时travel_log[country][city]['cities_visited'][restaurant]，您基本上是在使用 name 访问一个不存在的变量restaurant，而实际上，它是键的字符串名称，因此必须用引号引起来，'restaurant'因此正确的形式是travel_log[country][city]['cities_visited']['restaurant'].

完整代码：

for country in travel_log: 
  for city in travel_log[country]["cities_visited"]: # for Paris in France in Travel_log
    print(f"In {city}, {country} you visted {travel_log[country]['cities_visited'][city]['restaurant']}, {travel_log[country]['cities_visited'][city]['total_visits']} times.")

输出：

In Paris, France you visted Restaurant 1, 5 times.
In Lille, France you visted Restaurant 2, 2 times.
In Dijon, France you visted Restaurant 3, 3 times.

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