title: How to add values to existing dictionary key Python
body: <p>I am trying to create a function that takes in four parameters: A keyname, start time, end time, and then a dictionary. I have to create a tuple out of the start time and end time and then append that to a list of tuples, as we will be running this function multiple times. Then I am trying to put certain parts of the list of tuples to certain keynames. </p>
  
  <p>I think it's better if I would show you would the output looks like:</p>
  
  <pre><code>courses = insertIntoDataStruct(“CS 2316”, “1505”, “1555”, courses)  
  courses = insertIntoDataStruct(“CS 2316”, “1405”, “1455”, courses)  
  courses = insertIntoDataStruct(“CS 2316”, “1305”, “1355”, courses)  
  courses = insertIntoDataStruct(“CS 4400”, “1405”, “1455”, courses)  
  courses = insertIntoDataStruct(“CS 4400”, “1605”, “1655”, courses)    
  print(courses)  
  
  
  {'CS 2316': [(1505, 1555), (1405, 1455), (1305, 1355)], 'CS 4400': [(1405, 
  1455), (1605, 1655)]}
  </code></pre>
  
  <p>This is my code so far:</p>
  
  <pre><code>aDict = {}
  tupleList = []
  def insertIntoDataStruct(name,startTime,endTime,aDict):       
      timeTuple = tuple([startTime, endTime])  
      tupleList.append(timeTuple)
      aDict[name] = tupleList
      return aDict
  </code></pre>
  
  <p>I know that this will give me a dictionary with each key having ALL values, but I have no idea on how to make it so that each value that I add will be added on to the dictionary as seen in the output. I have tried a lot of random things, but I am still stuck on this. :(</p>