[REBOL] Interleaving strings -How? Re:
From: rebol:techscribe at: 21-Sep-2000 21:45
Hi Webdev,
>At bare minimum I need to understand the command
>syntax for stepping and clipping
>the string at specific points as well as the
>method for specifying the length of
>the clipped portion.
This should get you started
skip
>> string: "0123456789"
== "0123456789"
>> string: skip string 3
== "3456789"
>> string
== "3456789"
>> head string
== "0123456789"
>> string: head string
== "0123456789"
>> string
== "0123456789"
>> string skip tail string -3
== "789"
at
>> string: at string 3
== "23456789"
>> string
== "23456789"
>> string: head string
== "0123456789"
back
>> string back tail string
== "9"
next
>> string: next string
== "123456789"
>> string: head string
== "0123456789"
copy/part
>> partial-string: copy/part string 3
== "012"
>> partial-string
== "012"
>> partial-string: copy/part skip string 3 2
== "34"
>> partial-string
== "34"
Creating a string from an integer
>> string: form 1234
== "1234"
>> string
== "1234"
Another way to do it
>> string: ""
== ""
>> insert string 1
== ""
>> append string 2
== "12"
picking and poking
>> string
== "12"
>> pick string 1
== #"1"
>> pick string 2
== #"2"
>> poke string 2 #"X"
== "1X"
Hope this helps
At 11:30 PM 9/21/00 -0400, you wrote:
> Dear "Fellow Rebol Rousers", After having read the docs I have not
>quite figured out how to accomplish the interleaving of strings. The
>short and the long of what I want to do is take latitude and longitude
>coordinate pairs and interleave them with each other. The rational
>behind this is to place objects that are physically close to each other in
>the real world close together in computer memory, which we all know is
>linear and not spherical like the earth. The coordinates are in decimal
>degrees for the sake of easy manipulation. The max longitude is 180
>degrees while the max latitude is 90.
>Ignore the issue of positive/negative values as indications of north/south
>east/west locations. The first segment of the numbers would be
>interleaved on the basis of the non decimal portion of their values (1st
>three positions assuming required zero padding).
>The balance of the values would be interleaved on each subsequent pair.
>As an example: 043.6732452849
> 142.8321724625 interleaved value: 043142 6783 3221 4572 2846 4925
>(spaces are only for readability/illustration) The non decimal portion
>must be padded with a zero for all latitude values (they never exceed 90).
><100. I understand that I must convert the numbers to rebol strings to
>access the necessary functionality required to step through the "number"
>and pluck out the required portion. My problem: At bare minimum I need
>to understand the command syntax for stepping and clipping the string at
>specific points as well as the method for specifying the length of the
>clipped portion.
>Any inspiration would be most appreciated. Thanks in advance,
>[webdev--accglobal--net]
;- Elan [ : - ) ]
author of REBOL: THE OFFICIAL GUIDE
REBOL Press: The Official Source for REBOL Books
http://www.REBOLpress.com
visit me at http://www.TechScribe.com
