Tip: Sorting an Array of Objects

[kellyjonbrazil]

Python has great sorting capabilities, but sometimes it's not obvious how to do it. For example, many APIs will present their data as a JSON array of objects. Something like:

[
  {"foo": 5, "bar": 20},
  {"foo": 8, "bar": 100},
  {"foo": 10, "bar": 3} 
]

In Jello, this will be presented as a list of dictionaries. More accurately, it will be a list of DotMap objects which behave just like dictionaries except they allow using dot notation.

To sort this data, we need to decide which field to sort on and decide which method we would like to use. In either case, we will be using the Python builtin sorted() function and let's sort by the bar key.

Method 1 (lambda)

jello 'sorted(_, key = lambda i: i.bar)'

Method 2 (itemgetter)

jello '\
from operator import itemgetter
sorted(_, key=itemgetter("bar"))'

Both of these methods successfully sort the data by the desired key and provide the following output:

[
  {
    "foo": 10,
    "bar": 3
  },
  {
    "foo": 5,
    "bar": 20
  },
  {
    "foo": 8,
    "bar": 100
  }
]

The sorted() function also supports the reverse=[True|False] argument to sort descending vs. ascending order.