Named arguments vs Indexed

There is two ways of using arguments both has pros and cons, I want to emphasize that there is no “silver bluet” and you don’t have to choose one or another. You have to know both and use both whenever it appropriate.

Indexed arguments

Some application, languages, and even syntax contractions force you to use index version of arguments, they all well known and don’t worth to mention, but what is really interesting that some times we can use it in unexpected places.

in Postgres

Each of the arguments you specify in a select has a 1-based index and you can use these indexes in the order by as well as group by statements.

Instead of writing

select id, updated_at from posts order by updated_at;

you can write

select id, updated_at from posts order by 2;

If you want to group by a table’s type and then order by the counts from highest to lowest, you can do the following

select type, count(*) from transaction group by 1 order by 2 desc;

in Swift

Closure automatically provides shorthand argument names to inline closures, which can be used to refer to the values of the arguments by the names $0, $1, $2, and so on.

Instead of writing

reversed = names.sort({
    (s1: String, s2: String) -> Bool in
    return s1 > s2
  })

you can write

reversed = names.sort( { $0 > $1 } )