APL – A Glimpse of Heaven (2006)

Below, for example, there are two variables, a list of prices of 5 products and the quantity bought of each:

When the two variables are multiplied together, they are multiplied item by item to produce a result of the same shape:

This global approach eliminates most of the “loops” which greatly overburden programs in most current languages. The inventive creator of APL, Kenneth E. Iverson, therefore added to the set of all the usual symbols a number of new ones:

The symbol for the function maximum returns the greater of two numbers, or of two arrays of numbers compared item by item. And, of course, in the same way one may modify one or more items of designated by their indices, providing as many values are specified as there are items to modify, or a single value for all (modified items in bold type):

It is often necessary to extract the first items from a list of values, for example the first 5.

Source: vector.org.uk