OpenEuphoria

Re: 1 little sequence problem

• Posted by "Cuny, David at DSS" <David.Cuny at DSS.CA.GOV> Mar 17, 2000
• 410 views

=A9koda wrote:

> i get error message: variable s1 has not been assigned a value=20

true.

> subscript value 1 is out of bounds, assigning to a sequence of length =
0=20

think of the slice as trying to *replace* an existing item. so when you
write:

   s1[1] =3D i

you say:

   "replace the first item in the sequence s1 with i"

since there is no *first item* in s1 (it's empty, remember?), you get =
an
error.=20

these are logical errors of the same type. think of the sequence as an =
array
in this case - you can't ask for the nth item in the array if the array =
is
*smaller* than the index. in basic:

   dim s1[0]
   print s1[1]  <-- error, the array has zero items in it.

when you wrote:

   s1 =3D {}

you initialized the variable to an empty sequence - it still has no =
items in
it. so you can't ask for the nth item - there is no such animal. first
*fill* the sequence, and then replace the values, it will work:

   sequence s1
   ' fill it with 10 zeros
   s1 =3D repeat( 0, 10 )
   for i =3D 1 to 10 do
     ' replace the i'th zero with i
      s1[i] =3D i
   end for

in this case:

   s1 =3D repeat( 0, 10 )

is more or less akin to:

   dim s1[10]

or you could build the sequence by appending value to the end of it:

   sequence s1
   ' make it empty
   s1 =3D {}
   for i =3D 1 to 10 do
      ' append to the sequence
      s1 =3D s1 & i
   end for

or more succinctly, write:

      s1 &=3D i

insead of:

      s1 =3D s1 & i

Hope this helps!

-- David Cuny