[REBOL] Re: Newbie Q. wrt Strings
From: joel:neely:fedex at: 18-May-2001 7:47
Hi, Sanjay,
There are a couple of ways I can think of immediately.
Patel, Sanjay
wrote:
> My query is if I have a string say
>
> data: "this is a test no 2"
>
> how do I manipulate the string so that I am left with the
> number 2. Or pull out the number 2...
>
Here's the demo
>> do %firstint.r
>> data: "this is a test no 2"
== "this is a test no 2"
>> nodata: "there's no integer here"
== "there's no integer here"
>> find-first-int data
== 2
>> find-first-int nodata
== none
>> find-an-int data
== 2
>> find-an-int nodata
== none
and here's the code
8<------------------------------------------------------------
find-first-int: func [
s [string!]
/local digits nondigits partial
][
digits: charset [#"0" - #"9"]
nondigits: complement digits
partial: none
either parse/all s [
any non-digits
copy partial some digits
to end
][
to-integer partial
][
none
]
]
find-an-int: func [
s [string!]
][
foreach item to-block s [
if integer? item [ return item ]
]
none
]
8<------------------------------------------------------------
The first version, FIND-FIRST-INT, explicitly parses the data
string for a sequence of digit characters after skipping the
leading non-digit characters. It's more work, but it gives a
hint as to how you might handle more complex "find-the-data"
tasks.
The second version, FIND-AN-INT, lets REBOL do the heavy work
of figuring out what's in the string. It's less work, but it
depends on the fact that you're looking for something that
REBOL has a pre-conceived notion about.
Hope this helps!
-jn-
------------------------------------------------------------
Programming languages: compact, powerful, simple ...
Pick any two!
joel'dot'neely'at'fedex'dot'com
