Ordering

The Ordering usage message is shown below.

The next cell gives us the ordering of a list.

The next cell shows how we can take the results of Ordering and get a sorted

list. When Ordering is given one or two arguments we get the ordering of a

cononical sort which may not be the ordering of a numerically sorted list.

Ordering[lst,4] gives the first four elements of Ordering[lst]. The second

argument of Ordering can be (All) or an Integer meeting the condition

(-Length[list] ≤ n ≤ Length[list]). A few cells after

this example we use All as a a second argument for Ordering.

The next cell gives the last four elements of Ordering[lst].

The next cell gives the through the elements of Ordering[lst].

The output of the next cell returns with the element of Ordering[lst], and ends with the from the last element of Ordering[lst].

The next cell returns every other element of Ordering[lst] starting with the

first element of (lst) and ending with the last element of (lst).

As mentioned above Ordering normally gives the ordering of a cononical sort.

We can give Ordering a third argument to get the Ordering of another type of

sort. In the next cell we get the ordering of a numeric sort.

The next cell shows how we can take the results of the last Ordering and get

a numerically sorted list.

In all the examples above Ordering was given a list, but Ordering can work

with expressions having any head as shown in the next cell.

Created by Mathematica (May 16, 2004)