sorted

• sorted(iterable, key=key, reverse=reverse)
  • iterable: Required. The sequence to sort, list, dictionary, tuple etc.
  • key: Optional.
    • A Function to execute to decide the order. Default is None
    • “How should we sort the data?” (ex. len)
    • allows you to specify a function that will be applied to each element in the iterable. The result of this function is then used to determine the order of the sorting.
  • reverse: Optional. A Boolean. False will sort ascending, True will sort descending. Default is False
• A built in function that will work with other iterable collections (ex. tuple)

nums = [4,2,5,1]
sorted(nums) # [1,2,4,5], returns a copy of a list that is sorted
sorted(nums, reverse = True) # [5,4,2,1]
prints(nums) # [4,2,5,1]

• It returns a sorted copy, which is different from the sort method for list, which sorts the list in place
• You get a list no matter what type of iterable you put in

Using it on a list of dicts

• We use lambda
  • We use lambda in sorted if there are properties in the object (like different keys in a dictionary) and we want to sort by that object

users = [
	{"username": "samuel", "tweets": ["I love cake", "I love pie", "hello!"]},
	{"username": "katie", "tweets": ["I love my cat"]},
	{"username": "jeff", "tweets": [], "color": "purple"},
	{"username": "bob123", "tweets": [], "num": 10, "color": "teal"},
	{"username": "doggo_luvr", "tweets": ["dogs are the best", "I'm hungry"]},
	{"username": "guitar_gal", "tweets": []}
]
 
 
sorted(users) # ERROR
sorted(users, key=len) # number of keys in dict
 
# To sort users by each of their username alphabetically
sorted(users,key=lambda user: user['username'])
 
# Finding our most active users...
# Sort users by number of tweets, descending
sorted(users,key=lambda user: len(user["tweets"]), reverse=True)
 
# ANOTHER EXAMPLE DATA SET==================================
songs = [
	{"title": "happy birthday", "playcount": 1},
	{"title": "Survive", "playcount": 6},
	{"title": "YMCA", "playcount": 99},
	{"title": "Toxic", "playcount": 31}
]
 
# To sort songs by playcount
sorted(songs, key=lambda s: s['playcount'])