PERL Miscellaneous - Making sure a string is valid money number

Author

Making sure a string is valid money number

stevob@gmail.com

2005-11-27, 6:58 pm

I am trying to make sure a string that I have is in the format xxxxx.xx
(where x are digits only, and there can be any number of digits before
the . but only two after.) I have tried many different regex
combinations and I can't seem to get it to work. Here is what I have
most rescently that I think should work, but doesn't:
$amount=~/^[0-9]+(\.[0-9]{2})$/
Here is my thinking:
^[0-9]+ means that the begining of the string can only contain digits,
but as many as desired.
(\.[0-9]{2})$ means that, must contain a decimal and then only two
digits after that decimal at the end of the string.

Any help is appreciated.

Purl Gurl

2005-11-27, 6:58 pm

stevob wrote:

(snipped)

> I am trying to make sure a string that I have is in the format xxxxx.xx
> (where x are digits only, and there can be any number of digits before
> the . but only two after.) I have tried many different regex
> combinations and I can't seem to get it to work.

#!perl

$string = 123456.78;

if ((length(substr($string, rindex ($string, "."))) == 3) && (($string =~ tr/0-9//) == (length($string) - 1)))
{ print "Ok Boss"; }

Purl Gurl

Paul Lalli

2005-11-27, 6:59 pm

stevob@gmail.com wrote:
> I am trying to make sure a string that I have is in the format xxxxx.xx
> (where x are digits only, and there can be any number of digits before
> the . but only two after.) I have tried many different regex
> combinations and I can't seem to get it to work. Here is what I have
> most rescently that I think should work, but doesn't:
> $amount=~/^[0-9]+(\.[0-9]{2})$/

I see nothing particularly wrong [1] with that regexp, as it seems to
fit your description. Perhaps you could post a short-but-complete
script which demonstrates how it fails? (Have you read the Posting
Guidelines for this group?)

[1] The [0-9] tokens could be simplified to \d tokens, and the parens
are wholly unneeded, but neither of these are "wrong" per se.

Paul Lalli

Eric J. Roode

2005-11-27, 9:56 pm

stevob@gmail.com wrote in news:1133124499.039707.91950
@g44g2000cwa.googlegroups.com:

> I am trying to make sure a string that I have is in the format xxxxx.xx
> (where x are digits only, and there can be any number of digits before
> the . but only two after.) I have tried many different regex
> combinations and I can't seem to get it to work. Here is what I have
> most rescently that I think should work, but doesn't:
> $amount=~/^[0-9]+(\.[0-9]{2})$/
> Here is my thinking:
> ^[0-9]+ means that the begining of the string can only contain digits,
> but as many as desired.
> (\.[0-9]{2})$ means that, must contain a decimal and then only two
> digits after that decimal at the end of the string.

First, I would suggest using an existing wheel instead of reinventing:

use Regexp::Common;

$amount =~ /^$RE{num}{real}{-places=>2}$/;

However, if you wish to roll your own, presumably as a learning exercise,
that's fine too.

$amount=~/^[0-9]+(\.[0-9]{2})$/

This looks fine to me, other than that the parentheses are unnecessary.
You say it didn't work. That's not much information to go on. What
"didn't work"?

--
Eric
`$=`;$_=\%!;($_)=/(.)/;$==++$|;($.,$/,$,,$\,$",$;,$^,$#,$~,$*,$:,@%)=(
$!=~/(.)(.).(.)(.)(.)(.)..(.)(.)(.)..(.)......(.)/,$"),$=++;$.++;$.++;
$_++;$_++;($_,$\,$,)=($~.$"."$;$/$%[$?]$_$\$,$:$%[$?]",$"&$~,$#,);$,++
;$,++;$^|=$";`$_$\$,$/$:$;$~$*$%[$?]$.$~$*${#}$%[$?]$;$\$"$^$~$*.>&$=`

Matt Garrish

2005-11-27, 9:56 pm

"Purl Gurl" <purlgurl@purlgurl.net> wrote in message
news:rLydnSkG8PRyuBfeRVn-iA@giganews.com...
> stevob wrote:
>
> (snipped)
>
>
> #!perl
>
> $string = 123456.78;
>
> if ((length(substr($string, rindex ($string, "."))) == 3) && (($string =~
> tr/0-9//) == (length($string) - 1)))
>

You should write a book on how to write needlessly verbose code to avoid
having to understand regular expressions. It'd probably be a hit in the VB6
world.

Matt

Matt Garrish

2005-11-27, 9:56 pm

"Eric J. Roode" <sdn.girths00869@zoemail.net> wrote in message
news:Xns971BD2B3DD69Esdn.comcast@216.196.97.136...
> stevob@gmail.com wrote in news:1133124499.039707.91950
> @g44g2000cwa.googlegroups.com:
>
>
> First, I would suggest using an existing wheel instead of reinventing:
>
> use Regexp::Common;
>
> $amount =~ /^$RE{num}{real}{-places=>2}$/;
>
> However, if you wish to roll your own, presumably as a learning exercise,
> that's fine too.
>
> $amount=~/^[0-9]+(\.[0-9]{2})$/
>

But is there any need in this case to install a module and learn a new
syntax to replace a simple regular expression? Expecially since there was
nothing wrong with the code the OP posted?

Matt

Eric J. Roode

2005-11-29, 3:57 am

"Matt Garrish" <matthew.garrish@sympatico.ca> wrote in
news:aZtif.1416$wf2.122504@news20.bellglobal.com:

>
> But is there any need in this case to install a module and learn a new
> syntax to replace a simple regular expression? Expecially since there
> was nothing wrong with the code the OP posted?

No, not particularly. I just dislike reinventing wheels, and writing code
from scratch when someone else has done the same thing already.

--
Eric
`$=`;$_=\%!;($_)=/(.)/;$==++$|;($.,$/,$,,$\,$",$;,$^,$#,$~,$*,$:,@%)=(
$!=~/(.)(.).(.)(.)(.)(.)..(.)(.)(.)..(.)......(.)/,$"),$=++;$.++;$.++;
$_++;$_++;($_,$\,$,)=($~.$"."$;$/$%[$?]$_$\$,$:$%[$?]",$"&$~,$#,);$,++
;$,++;$^|=$";`$_$\$,$/$:$;$~$*$%[$?]$.$~$*${#}$%[$?]$;$\$"$^$~$*.>&$=`

foo bar baz qux

2005-11-29, 6:59 pm

Matt Garrish wrote:
> "Purl Gurl" <purlgurl@purlgurl.net> wrote in message
> news:rLydnSkG8PRyuBfeRVn-iA@giganews.com...
>
> You should write a book on how to write needlessly verbose code to avoid
> having to understand regular expressions. It'd probably be a hit in the VB6
> world.
>

But wait, Kira[1] loves useless benchmarks, lets try one:

Benchmark: timing 10000000 iterations of callgirl, steveob...
callgirl: 17 wallclock secs (16.22 usr + 0.00 sys = 16.22 CPU) @
616598.84/s
steveob: 15 wallclock secs (14.41 usr + 0.00 sys = 14.41 CPU) @
694155.21/s

Gee Kira's code is slower[2] as well as being needlessly verbose.

[1] Kiralynne Schilitubi AKA callgirl AKA Godzilla AKA Purl Gurl etc
[2] Kira really cares about shaving nanoseconds off her run times and
frequently uses this to hotly justify Kira's peculiar coding practices.

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