OpenEuphoria

Basic Sequences -- Jim C.

• Posted by Al Getz <Xaxo at aol.com> Mar 16, 2001
• 479 views

Hi Jim,

    Here is some info to supplement what's already been posted.


It helps to think of a sequence as a list, as
that's what it really is anyway.  To access
items of the list, simply use the name of
the list followed by the number of the
element in the list enclosed in [ ]
like this:
    name[2] -- to access the second item on the list.
    name[3] -- to access the third item on the list.


Here's an example:

--an enumerated real world list called 'list A':
    [1] cat
    [2] dog
    [3] mouse
    [4] 3.14159

--let's code that same list in Euphoria:
    sequence A
    A={"cat","dog","mouse",3.14159}
    
--let's print out that A list to the screen:
    puts(1,A[1])
    puts(1,'\n')

    puts(1,A[2])
    puts(1,'\n')

    puts(1,A[3])
    puts(1,'\n')

    print(1,A[4]) --use 'print' for a number
    puts(1,'\n')

--now let's view the structure of the first item on the list
--instead of just displaying it in the usual way:
    print(1,A[1])
    puts(1,'\n')


       Some notes to think about:

Take note that puts(1,A[1]) and print(1,A[1]) give us
two different views of the same item of the list.
Like Kat was saying, you may want to experiment with
various ways of printing your sequence items before
you get involved with command_line() arguments.
Learning to print out data is an important part of
programming, at some point or another you will
need to print out your data correctly in order
to effectively debug your advanced programs.

Also note that in order to access an item, say A[3],
that item must already exist.  In our list above
(list A) we wouldnt be able to execute:
    puts(1,A[5])
for the simple reason that we didnt store anything
on the list at would-be-location A[5] yet.  In this
case an error would occur and the program would halt.

Sequences are a little strange even for experienced
programmers who are used to using more 'well defined'
data types.  Once they are mastered, the problems
diminish rapidly.


Good luck with it.
--Al
"Understanding is just around the corner from experimentation."