title: Python Creating a dictionary of dictionaries structure, nested values are the same
body: <p>I'm attempting to build a data structure that can change in size and be posted to Firebase. The issue I am seeing is during the construction of the data structure. I have the following code written: </p>
  
  <pre><code>for i in range(len(results)):
  designData = {"Design Flag" : results[i][5],
          "performance" : results[i][6]}
  for j in range(len(objectiveNameArray)):
      objectives[objectiveNameArray[j]] = results[i][columnHeaders.index(objectiveNameArray[j])]
  designData["objectives"] = copy.copy(objectives)
  for k in range(len(variableNameArray)):
      variables[variableNameArray[k]] = results[i][columnHeaders.index(variableNameArray[k])]
  designData["variables"] = copy.copy(variables)
  for l in range(len(responseNameArray)):
      responses[responseNameArray[l]] = results[i][columnHeaders.index(responseNameArray[l])]
  designData["responses"] = copy.copy(responses)
  for m in range(len(constraintNameArray)):
      constraintViolated = False
      if constraintNameArray[m][1] == "More than":
          if results[i][columnHeaders.index(constraintNameArray[m][0])] &gt; constraintNameArray[m][2]:
              constraintViolated = True
          else:
              constraintViolated = False
      elif constraintNameArray[m][1] == "Less than":
          if results[i][columnHeaders.index(constraintNameArray[m][0])] &lt; constraintNameArray[m][2]:
              constraintViolated = True
          else:
              constraintViolated = False
      if constraintNameArray[m][0] in constraints:
          if constraints[constraintNameArray[m][0]]["violated"] == True:
              constraintViolated = True
      constraints[constraintNameArray[m][0]] = {"value" : results[i][columnHeaders.index(constraintNameArray[m][0])], "violated" : constraintViolated}
  designData["constraints"] = copy.copy(constraints)
  data[studyName][results[i][4]] = designData
  </code></pre>
  
  <p>When I include print(designData) inside of the for loop, I see that my results are changing as expected for each loop iteration.</p>
  
  <p>However, if I include print(data) outside of the for loop, I get a data structure where the values added by the results array are all the same values for each iteration of the loop even though the key is different. </p>
  
  <p><a href="http://i.stack.imgur.com/XAtis.png" rel="nofollow">Comparing print(data) and print(designData)</a></p>
  
  <p>I apologize in advance if this isn't enough information this is my first post on Stack so please be patient with me. </p>