python sort list of dictionaries alphabetically

#PYTHON SORT LIST OF DICTIONARIES ALPHABETICALLY HOW TO#
#PYTHON SORT LIST OF DICTIONARIES ALPHABETICALLY MANUAL#

Note that this kind of scenario is a bit unusual in that…well, what is the purpose of sorting a list that contains text strings and numbers? The answer: um…I don't know. How about sorting a list that contains numbers and strings? The sorted function – and the key function that it calls – never alters the original list. Note how the resulting list contains the original values, but sorted according to the result of my_foo being called upon each item. upper () mylist = sorted ( mylist, key = my_foo ) Here's all the code, all together: def my_foo ( item ): return item. upper ()Īnd now we can pass my_foo into the sorted function. That function is fairly trivial to write: def my_foo ( item ): return item. Essentially, we tell the sorted function: hey, sort each item in this list not by the item's actual value, but by some transformation of its value.įor the current scenario, the 'transformation' of the value is simply: the uppercased version of the string. What a key function allows us to do is delegate that work to the sorted function.

#PYTHON SORT LIST OF DICTIONARIES ALPHABETICALLY MANUAL#

Of course, doing that manual conversion has a lot of disadvantages, the primary one being that you have to manually convert each item in the list. One way to do this is to convert everything to either all-upper or all-lower case characters: > my_big_list = > sorted ( my_big_list ) But in other situations, we might want the strings to be sorted alphabetically without regard to capitalization. Remember that while text strings are seemingly sorted in alphabetical order, uppercase characters take precedence: > sorted ( mylist ) Īnd maybe that's what we want. Here's an actual example: how do we sort a list of text strings that have different kinds of capitalization? mylist =

#PYTHON SORT LIST OF DICTIONARIES ALPHABETICALLY HOW TO#

Which means that a function by that name has to actually be defined: def some_function_name ( item ): return do_something ( item ) # obviously, do_something is some other hypothetical function # that also has to be defined sorted (, key = some_function_name ) How to sort apples and oranges and numbers Instead, we have to pass in the name of a function, a function that defines how each object in the collection should be evaluated as for sorting purposes: sorted (, key = some_function_name ) However, the key argument does not take a simple value, such as True. If we want things to be sorted in reverse-order (which would be descending order for character strings and numbers), pass True to the reverse argument: > mylist = > sorted ( mylist ) > sorted ( mylist, reverse = True ) Defining a key functionīesides a reverse argument, the sorted function takes one other named argument: key. The sorted function takes a named argument, reverse, which is set to False by default. Try to apply that factoid in explaining this seemingly contradictory result: > sorted () > sorted () Sorting in reverse with sorted

the character '1' has a value of 49: > sorted ()

Which should explain this result: > sorted () Īnd when numbers are represented as strings, they are not sorted in numerical order, but by their binary/hexadecimal value, e.g.

Since every digital object is ultimately just a bunch of ones and zeros, letters and numbers are actually sorted by their binary values, e.g. Of course, even that is more complicated than you might think. from lowest to highest, and alphabetically. Sorting alphabetically and numerically with sortedīy default, sorted will return numbers and text strings in ascending order, i.e. …but, for the most part, we'll be dealing with lists. Strings, for example, are iterable: > sorted ( 'Hello World!' ) Note: by ' iterable collection', I mean that sorted can deal with sequences other than lists. It's when we want to sort a collection of objects that are not all the same that things get slightly more complicated: > sorted () TypeError : unorderable types : int () > mylist = > sorted ( mylist ) Python Dictionaries Access Items Change Items Add Items Remove Items Loop Dictionaries Copy Dictionaries Nested Dictionaries Dictionary Methods Dictionary Exercise Python If.Else Python While Loops Python For Loops Python Functions Python Lambda Python Arrays Python Classes/Objects Python Inheritance Python Iterators Python Polymorphism Python Scope Python Modules Python Dates Python Math Python JSON Python RegEx Python PIP Python Try.In Python, as in most high-level programming languages, it's very easy to sort a list of simple objects such as numbers or text strings: > sorted () > sorted ()

Python sort list of dictionaries alphabetically