Re: another newbie question
Hi Kat,
Hope this helps.
> I have ordered an epiphany, and i hope it is delivered soon, so i can
really
> grasp exactly and fully all the implications of the preceeding and revel
in
> it, but for now, how do i avoid the following error msg with a test
> preceeding the print statement?
According to the Euphoria Programming Language Reference Manual:
---
2.1.1 Atoms and Sequences
All data objects in Euphoria are either atoms or sequences. An atom is a
single numberic value. A sequence is a collection of numeric values.
---
Now to me this says that a SEQUENCE is really just a collection of ATOMs all
strung together. Also indicated by the fact that while tracing a program
any variable that is a 'string' (or collection of readable letters) is
displaied as its ASCII value. RDS was thoughtful enough to supply the
letter equivelant of any number that is a printable ASCII character along
with that number.
Now, your problem seems to be getting a handle on nested sequences.
Another way to look at a sequence is that it is a one-dimentional array of
atoms.
With that in mind, a nested sequence is just a multi-dimentional array of
atoms.
>Given:
>sentword = {"test1",{"test2","test3"}}
>
>printf(1,"%s\n", sentword[1] )
>-- prints: t
Given the examples that you provided. The 't' that you ended up with is
the first 't' from "test1". You only got the 't' because 'sentword[1]' by
itself indicates to Euphoria that you are only interested in an atom.
>printf(1,"%s\n", {sentword[1]} )
>-- prints: test1
What you get here is obviously "test1". The '{' and '}' indicate to
Euphoria that you are interested in the sequence that is at subscript 1
>printf(1,"%s\n", sentword[2] )
>-- prints: test2
This one is probably where you are getting really confused. I have been
messing with it a little and I find it slightly confusing too. If you do
some more testing you will find that :
printf(1,"%s\n", {sentword[2] })
Generates this error: sequence found inside character string
If I understand this correctly with this expression Euphoria is expecting to
find a single sequence in subscript two when there is in reality two
sequences inside sequence two. {"test2","test3"} This is two sequences of
characters.
On first glance it would seem that printing sentword[2] would give you a 't'
like it did with sentword[1]. However, it looks like since sentword[2] is a
subscript itself that Euphoria picks up the first element of the substring.
That being "test2".
I am reading this as I go and I am starting to confuse myself. I think that
we need to look at this problem the way that Euphoria is looking at it.
What Euphoria actually sees is more along the lines of :
I thik this is a little more obvious. There is a nesting of sequences that
is three deep. I think that the following can be extrapilated from this.
printfing -- sentword[1] gives the first element that it finds in the first
subscript. 116
printfing -- {sentword[1]} gves the first sequence that it finds in the
first subscript. 116,101,115,116,49
printfing -- sentword[2] gives the first element that it finds in the second
subscript. {116,101,115,116,50} which just happens to be a sequence.
printfing -- {sentword[2]} gives an error because it is looking for a
sequence and finds a sequence of sequences because you are trying to format
it as a string and Euphoria sees a string of strings which is evidently not
valid.
printfing -- sentword[2][1] gives the first element of the first
sub-subscript of the second subscript. 116
printfing -- {sentword[2][1]} gives the sequence that it finds in first
sub-subscript of the second subscript. 116,101,115,116,50
Now, after all that. I hope that this at least makes some sense to someone.
I am hoping that it makes sense to Kat because that is who it was meant for.
I would recomend reading Part I chapter 2 of the Reference Manual. I think
that it goes over this stuff quite well. As I am trying to explain this I
am reading the manual and playing with Euphoria in another window. Gets a
little confusing after a while.
Good luck on the arrival of your epiphany. I hope that it is everything
that you are expecting.
> Kat,
> foolishly trying to make it simple.
> Or is it too simple already?
Till next time.
L8R
Glen
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