title: How to change the value of a key in a nested dictionary in Python
body: <pre><code>{
   {'city':1 ,'person':{'name': 'John', 'age': '27'}},
   {'city':2 ,'person':{'name': 'Marie', 'age': '22'}},
   {'city':3 ,'person':{'name': 'Luna', 'age': '24'}},
   {'city':4 ,'person':{'name': 'Peter', 'age': '29'}}
  }
  </code></pre>
  
  <p>How to change the age of the person in city 2 ?</p>
  
  <p>And the second part of my question is that in Python which data structure is the most relevant in this case</p>