Solved

numeric or string ??

Posted on 1998-06-12
10
210 Views
Last Modified: 2010-03-05
Hi,

I would like to know if they have a way to analyse a value receive from a FORM, if it's a numeric number or a string ?

Thank.
0
Comment
Question by:woaini
  • 3
  • 3
  • 2
  • +2
10 Comments
 
LVL 84

Expert Comment

by:ozo
Comment Utility
What do you consider a numeric number?
Have you tried the answers in perlfaq4 for "How do I determine whether a scalar is a number/whole/integer/float?"
0
 

Author Comment

by:woaini
Comment Utility
Hi,

I mean by numeric = number . No, I haven't tried the answer in perlfaq4. Can you tell me where the location is ?

Thank.
0
 
LVL 84

Expert Comment

by:ozo
Comment Utility
Is "009" a number? "10e"? "10e-999"? "0xFF"? "1/2"? "Q.10057609"? "-inf"? "two"?  "four score and seven"?

perldoc perlfaq4
in the "Data: Misc" section.



0
 

Author Comment

by:woaini
Comment Utility
0.10 ; 0.50 ; 1 ; 123 are number.
And "yes" or "no" are string.


0
 
LVL 28

Expert Comment

by:sybe
Comment Utility
Form values are passed as a string, if you want to use them as a number and you are not sure that it can be converted to a number, you should convert it to a number and catch an eventual error.

0
What Security Threats Are You Missing?

Enhance your security with threat intelligence from the web. Get trending threat insights on hackers, exploits, and suspicious IP addresses delivered to your inbox with our free Cyber Daily.

 
LVL 51

Accepted Solution

by:
ahoffmann earned 20 total points
Comment Utility
beside ozo's comments, would folloing do what you expect?

$_=$string_to_check_if_numeric;
print "$_\n" if m/^[0-9]+\.?$|^[0-9]*\.?[0-9]+$/;
0
 
LVL 84

Expert Comment

by:ozo
Comment Utility
print /[^\d.]/?"string":"number"; # might suffice for your examples
but it may or may not do what you want for "  .5\n", "+12300.e-2", "01", "", "1e9999", etc.
If you're not sure what you want to do in those cases, or if you're not sure which of the FAQ examples is most suitable for your purposes, perhaps you can tell us what you're trying to do with your values?
0
 
LVL 5

Expert Comment

by:b2pi
Comment Utility
> beside ozo's comments, would folloing do what you expect?

>     $_=$string_to_check_if_numeric;
>     print "$_\n" if m/^[0-9]+\.?$|^[0-9]*\.?[0-9]+$/;

Probably not, at least in the general case.  Remember that a number may have an ignored underbar (i.e. 9_000 is legit... an Ada-ism).  Also, 4.7e12 is a legitimate number, which would fail your test.

ozo's comments about see the faq are relevant.  Tom covers this question exhaustively (btw, the final answer he gives is really 'you probably don't need to...')

0
 
LVL 51

Expert Comment

by:ahoffmann
Comment Utility
b2pi, I know that my answer didn't cover *all* possibilities of writing "numbers", I just want it to be sufficent for woaini.
You even may think about pi, e (==euler), 2/3, and some more which are also legal "numbers" in some contexts.

If you would like to see a more perfect regex, have a look at the "Regualr Expressions" book and you'll see that even in perl it doesn't fit in a single line :-)

BTW, ozo's \d is more perlish than [0-9] (which I like for readability).
0
 

Author Comment

by:woaini
Comment Utility
Thank a lot !
0

Featured Post

How your wiki can always stay up-to-date

Quip doubles as a “living” wiki and a project management tool that evolves with your organization. As you finish projects in Quip, the work remains, easily accessible to all team members, new and old.
- Increase transparency
- Onboard new hires faster
- Access from mobile/offline

Join & Write a Comment

Email validation in proper way is  very important validation required in any web pages. This code is self explainable except that Regular Expression which I used for pattern matching. I originally published as a thread on my website : http://www…
I have been pestered over the years to produce and distribute regular data extracts, and often the request have explicitly requested the data be emailed as an Excel attachement; specifically Excel, as it appears: CSV files confuse (no Red or Green h…
Explain concepts important to validation of email addresses with regular expressions. Applies to most languages/tools that uses regular expressions. Consider email address RFCs: Look at HTML5 form input element (with type=email) regex pattern: T…
In this tutorial you'll learn about bandwidth monitoring with flows and packet sniffing with our network monitoring solution PRTG Network Monitor (https://www.paessler.com/prtg). If you're interested in additional methods for monitoring bandwidt…

772 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

10 Experts available now in Live!

Get 1:1 Help Now