How to sort python dict based on multiple dict keys?

Question

For the following data, I am looking to sort the data first by the "date" property, and then by the "name" property.

Input:
results = {
   "a":{
      "date":"20140206",
      "bytes":"154",
      "name":"cos"
   },
   "b":{
      "date":"20140207",
      "bytes":"300",
      "name":"cos"
   },
   "c":{
      "date":"20140206",
      "bytes":"279",
      "name":"phil"
   },
   "d":{
      "date":"20140207",
      "bytes":"241",
      "name":"phil"
   }
}

I am trying the following code which works but I am not sure how it is sorting first by date and then by name.

results = collections.OrderedDict(sorted(results.items()))

Output:
results = {
   "a":{
      "date":"20140206",
      "bytes":"154",
      "name":"cos"
   },
   "c":{
      "date":"20140206",
      "bytes":"279",
      "name":"phil"
   },
   "b":{
      "date":"20140207",
      "bytes":"300",
      "name":"cos"
   },
   "d":{
      "date":"20140207",
      "bytes":"241",
      "name":"phil"
   }
}

Is there any other way to do it where I can explicitly specify to first sort by date property and then by name property?

Answer 1

You have to use key= for custom sorting.

If you want to sort first by date then by name you need to use tuple of them as a sorting key

results = collections.OrderedDict(sorted(results.items(), key=lambda s: (s[1]['date'], s[1]['name'])))