At 11:12 AM 8/14/01 -0700, you wrote:
>Hi Peter,
>Can you be more specific?
>so I can use $foo = "string";
>and then what?
Then you type "perldoc -f substr" to learn about the substr function. You
should see something like this, which contains all the information you need
plus examples:
substr EXPR,OFFSET,LENGTH,REPLACEMENT
substr EXPR,OFFSET,LENGTH
substr EXPR,OFFSET
Extracts a substring out of EXPR and returns it.
First character is at offset "0", or whatever you've
set "$[" to (but don't do that). If OFFSET is
negative (or more precisely, less than "$["), starts
that far from the end of the string. If LENGTH is
omitted, returns everything to the end of the
string. If LENGTH is negative, leaves that many
characters off the end of the string.
You can use the substr() function as an lvalue, in
which case EXPR must itself be an lvalue. If you
assign something shorter than LENGTH, the string
will shrink, and if you assign something longer than
LENGTH, the string will grow to accommodate it. To
keep the string the same length you may need to pad
or chop your value using "sprintf".
If OFFSET and LENGTH specify a substring that is
partly outside the string, only the part within the
string is returned. If the substring is beyond
either end of the string, substr() returns the
undefined value and produces a warning. When used
as an lvalue, specifying a substring that is
entirely outside the string is a fatal error.
Here's an example showing the behavior for boundary
cases:
my $name = 'fred';
substr($name, 4) = 'dy'; # $name is now 'freddy'
my $null = substr $name, 6, 2; # returns '' (no warning)
my $oops = substr $name, 7; # returns undef, with
warni
ng
substr($name, 7) = 'gap'; # fatal error
An alternative to using substr() as an lvalue is to
specify the replacement string as the 4th argument.
This allows you to replace parts of the EXPR and
return what was there before in one operation, just
as you can with splice().
>Thanks for your help.
>
>Eric
>
>
>On Tue, 14 Aug 2001, Peter Scott wrote:
>
> > An associative array is the old name for a hash, which isn't what
> you're using.
> >
> > At 10:14 AM 8/14/01 -0700, Eric Wang wrote:
> > >Hi guys,
> > >
> > >Got a quick question.
> > >If I let @foo = "some string";
> > >can I access say the "t" in this string by using $foo[6] ?
> >
> > You've got a scalar which you want to treat as an array. Put the string in
> > a scalar, and use the substr() function (perldoc -f substr).
> >
> > --
> > Peter Scott
> > Pacific Systems Design Technologies
> > http://www.perldebugged.com
> >
> >
> > --
> > To unsubscribe, e-mail: [EMAIL PROTECTED]
> > For additional commands, e-mail: [EMAIL PROTECTED]
> >
--
Peter Scott
Pacific Systems Design Technologies
http://www.perldebugged.com
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