[PATCH perlfaq4] 'is a number?' updated
[email protected] (Iain Truskett)
| Newsgroups | perl.perlfaq.workers |
|---|---|
| Message-ID | <[email protected]> |
Update to reflect the inclusion of Scalar::Util into core. Style note: I note the FAQ takes the correct approach and calls it 'the CPAN'. Contemporary usage has it as just 'CPAN'. I assume 'correct' is favoured over 'popular'? cheers, -- Iain.
isanumber.patch
(text/plain, 1.7 KB)
? dif
? isnum
Index: perlfaq4.pod
===================================================================
RCS file: /cvs/public/perlfaq/perlfaq4.pod,v
retrieving revision 1.47
diff -u -r1.47 perlfaq4.pod
--- perlfaq4.pod 25 Aug 2003 05:58:04 -0000 1.47
+++ perlfaq4.pod 13 Sep 2003 14:08:34 -0000
@@ -1990,11 +1990,15 @@
if (/^([+-]?)(?=\d|\.\d)\d*(\.\d*)?([Ee]([+-]?\d+))?$/)
{ print "a C float\n" }
-You can also use the L<Data::Types|Data::Types> module on
-the CPAN, which exports functions that validate data types
-using these and other regular expressions, or you can use
-the C<Regexp::Common> module from CPAN which has regular
-expressions to match various types of numbers.
+There are also some commonly used modules for the task.
+L<Scalar::Util> (core from 5.8) provides access to Perl's
+internal function C<looks_like_number> for determining
+whether a variable looks like a number. L<Data::Types>
+exports functions that validate data types using both the
+above and other regular expressions. Thirdly, there is
+C<Regexp::Common> which has regular expressions to match
+various types of numbers. Those three modules are available
+from the CPAN.
If you're on a POSIX system, Perl's supports the C<POSIX::strtod>
function. Its semantics are somewhat cumbersome, so here's a C<getnum>
@@ -2019,7 +2023,7 @@
sub is_numeric { defined getnum($_[0]) }
-Or you could check out the L<String::Scanf|String::Scanf> module on the CPAN
+Or you could check out the L<String::Scanf> module on the CPAN
instead. The POSIX module (part of the standard Perl distribution) provides
the C<strtod> and C<strtol> for converting strings to double and longs,
respectively.