Lyle Kopnicky wrote:
Thanks folks. I think I'll go with looks_like_number from
Scalar::Util. I like to use library routines where possible. I don't
know how I overlooked that, since I poked through Scalar::Util earlier.
It just seems bizarre to me that something like that isn't a
Wow there's been a lot of heavy duty code proposed to do something so
simple. The answer is in how Perl converts between the two.
print is a number if $var eq $var + 0;
print not a number if $var ne $var + 0;
Say $var is bob. In the first case we see if bob is string equal to bob
+ 0 or is bob
Wow there's been a lot of heavy duty code proposed to do something so
simple. The answer is in how Perl converts between the two.
print is a number if $var eq $var + 0;
print not a number if $var ne $var + 0;
That fails on 1e7.
___
Title: Re: Test if string is a number?
Chris Wagner wrote, on Thu 6/30/2005 08:48
: Wow there's been a lot of heavy duty code proposed to do
something so: simple. The answer is in how Perl converts between the
two.:: print "is a number" if $var eq $var + 0;: print "not a
Chris Wagner wrote:
Wow there's been a lot of heavy duty code proposed to do something so
simple. The answer is in how Perl converts between the two.
print is a number if $var eq $var + 0;
print not a number if $var ne $var + 0;
Say $var is bob. In the first case we see if bob is string
Title: Re: Test if string is a number?
How about regexp?
/^\-?(\d+\.?\d*|\.\d+)$/
- Original Message -
From:
Joe
Discenza
To: Chris Wagner ; perl-win32-users
Sent: Thursday, June 30, 2005 4:48
PM
Subject: RE: Test if string is a
number?
Chris Wagner
: Test if string is a number?
How about regexp?
/^\-?(\d+\.?\d*|\.\d+)$/
- Original Message -
From: Joe Discenza
To: Chris Wagner ; perl-win32-users
Sent: Thursday, June 30, 2005 4:48 PM
Subject: RE: Test if string is a number?
Chris Wagner wrote, on Thu 6/30/2005 08:48
: Wow there's
At 09:48 AM 6/30/05 -0500, Joe Discenza wrote:
Except if $var is, say, '0.00'. Then $var + 0 is '0', and won't eq $var.
0.00 is not a valid internal representation of a number. That can only
exist as a string. Same goes for 1e7. That is a print formated number,
not a valid internal number.
[EMAIL PROTECTED] wrote:
0.00 is not a valid internal representation of a number.
That can only exist as a string.
I think u need to re-read the subject of this thread.
- Mark.
___
Perl-Win32-Users mailing list
Title: RE: Test if string is a number?
Chris Wagner wrote, on Thu 6/30/2005 12:41
: At 09:48 AM 6/30/05 -0500, Joe Discenza wrote:: Except
if $var is, say, '0.00'. Then $var + 0 is '0', and won't eq $var.:: 0.00
is not a valid internal representation of a number. That can only:
exist
At 12:16 PM 6/30/05 -0500, Joe Discenza wrote:
I bet you're right that eval($var) eq $var + 0 works; have you
benchmarked it against all the other (regex, e.g.) methods presented?
I haven't benchmarked it but I can garuntee that it's faster than a regex.
Anything's faster than that. ;) This
Title: RE: Test if string is a number?
Chris Wagner wrote, on Thu 6/30/2005 14:41
: At 12:16 PM 6/30/05 -0500, Joe Discenza wrote:: I bet
you're right that "eval($var) eq $var + 0" works; have you: benchmarked
it against all the other (regex, e.g.) methods presented?::
Joe Discenza wrote:
Chris Wagner wrote, on Thu 6/30/2005 14:41
: At 12:16 PM 6/30/05 -0500, Joe Discenza wrote:
: I bet you're right that eval($var) eq $var + 0 works; have you
: benchmarked it against all the other (regex, e.g.) methods presented?
:
: I haven't benchmarked it but I can
At 02:28 PM 6/30/05 -0500, Joe Discenza wrote:
Regex is pretty fast. Eval is usually pretty slow.
Yeah ur right about the eval. I did a triple head to head with ur regex and
eval/no eval. The eq without the eval demolishes all.
Rate evalRE noeval
eval3397/s -- -87%
Thanks folks. I think I'll go with looks_like_number from
Scalar::Util. I like to use library routines where possible. I don't
know how I overlooked that, since I poked through Scalar::Util earlier.
It just seems bizarre to me that something like that isn't a builtin. I
mean, you can't
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