Sort months ( with strings ) algorithm

Question

I have this months array:

[\"January\", \"March\", \"December\" , \"October\" ]

And I want to have it sorted like this:

[\"         


        

Answer 1

For something like months, I'd just hard-code the arrays I needed...

var correctOrdering = {
    english: ["January", "February", "March", ...],
    french: ["Janvier", "Février", "Mars", ...],
    russian: ["Январь", "февраль", "март"],
    ...
};

It's not like month names are going to change any time soon.

Answer 2

Create a mapping:

month_map = {"January":1,
             "February":2,
             "March":3,
             "April":4} # etc..

Use the mapping to compare one month to the other.

OR

Most languages/frameworks have objects for handling dates. Create date objects for all the months and compare them using the native (if available) inequality operators or basic sorting functions:

import datetime
January  = datetime.date(2010,1,1)
February = datetime.date(2010,2,1)
if February < January: print("The world explodes.")

Answer 3

Add a prefix for each month:

Jan -> aJan
Feb -> bFeb
...

Sort, then remove the prefix.

Answer 4

tl;dr

EnumSet.of( Month.JANUARY , Month.MARCH , Month.OCTOBER , Month.DECEMBER ).toString()

Enum

If your language provides a powerful enum facility as does Java, define a dozen objects. See Oracle Tutorial.

java.time.Month

The java.time classes include the handy Month enum, defining a dozen objects one for each month of the year January-December.

They are numbered 1-12, and defined in proper order, January to December.

In your code base, use objects of this enum to replace any use of mere integers or use of name-of-month strings. Using Month objects throughout provides type-safety, ensures valid values, and makes your code more self-documenting.

In Java, the EnumSet and EnumMap are implementations of Set and Map that are optimized for enum values. They execute very quickly and take very little memory.

EnumSet<Month> months = EnumSet.of( Month.JANUARY , Month.MARCH , Month.OCTOBER , Month.DECEMBER );

The EnumSet iterates in natural order, the order in which the enum constants are declared. So no need to explicitly sort your collection.

The class includes a getDisplayName method for generating a localized String of the name of the month. Specify a TextStyle for how long or abbreviated you want the text. And specify a Locale for (a) the human language to use in translation, and (b) the cultural norms to decide issues such as abbreviation, punctuation, and capitalization.

for( Month month : months ) {
    String output = month.getDisplayName( TextStyle.SHORT_STANDALONE , Locale.CANADA_FRENCH );  // Or Locale.US, Locale.ITALY, etc.
    System.out.println( output );
}