Best way to check if string is numeric

[tshad]

I have a string field and a decimal fields and was wondering what the best
way to check for numeric is?

I have to do something like:

If (myAmount is numeric)
{
total += myAmount;
}

Thanks,

Tom

[Kalpesh]

Re: Best way to check if string is numeric

Use Decimal.Parse or TryParse.
All the numeric datatype might have Parse & TryParse.

Kalpesh

On Dec 18, 11:02 am, "tshad" <t...@dslextrem e.comwrote:

I have a string field and a decimal fields and was wondering what the best
way to check for numeric is?
>
I have to do something like:
>
If (myAmount is numeric)
{
total += myAmount;
>
}
>
Thanks,
>
Tom

[GS]

Re: Best way to check if string is numeric

don't know if the best but you cant ry something along the line of

private static Rage _isNumber = new Rage(@"^\d+$");

public static bool IsInteger(strin g theValue)
{
Match m = _isNumber.Match (theValue);
return m.Success;
} //IsInteger



"tshad" <tfs@dslextreme .comwrote in message
news:uGrJRuTQIH A.5160@TK2MSFTN GP05.phx.gbl...

I have a string field and a decimal fields and was wondering what the best
way to check for numeric is?
>
I have to do something like:
>
If (myAmount is numeric)
{
total += myAmount;
}
>
Thanks,
>
Tom
>
>

[Michael Nemtsev [MVP]]

Re: Best way to check if string is numeric

Hello GS,

"If u have a promblem an gonna solve it with RegExp then now u have two problems"
(c) dont remember who

---
WBR,
Michael Nemtsev [.NET/C# MVP] :: blog: http://spaces.live.com/laflour

"The greatest danger for most of us is not that our aim is too high and we
miss it, but that it is too low and we reach it" (c) Michelangelo


Gdon't know if the best but you cant ry something along the line of
Gprivate static Rage _isNumber = new Rage(@"^\d+$");
Gpublic static bool IsInteger(strin g theValue)
G{
GMatch m = _isNumber.Match (theValue);
Greturn m.Success;
G} //IsInteger

[Jon]

Re: Best way to check if string is numeric

If I remember correctly, a possible down-side with .Parse and .TryParse is that if you're trying to
read a number that is not terminated in white space (eg 25k) it will produce an error since it
regards the k in this case as invalid. This only matters of course if your number doesn't end in
white space.


"Kalpesh" <shahkalpesh@gm ail.comwrote in message
news:f25d0a6e-f923-4485-843b-6aa0d83dabfb@i2 9g2000prf.googl egroups.com...
Use Decimal.Parse or TryParse.
All the numeric datatype might have Parse & TryParse.

Kalpesh

[GS]

Re: Best way to check if string is numeric

true enough if one doesn't use regexp to begin with.
of course try parse will be better for some application

"Michael Nemtsev [MVP]" <nemtsev@msn.co mwrote in message
news:3d9fba1a20 e7e8ca0fbe373aa 890@msnews.micr osoft.com...

Hello GS,
>
"If u have a promblem an gonna solve it with RegExp then now u have two

problems"

(c) dont remember who
>
---
WBR,
Michael Nemtsev [.NET/C# MVP] :: blog: http://spaces.live.com/laflour
>
"The greatest danger for most of us is not that our aim is too high and we
miss it, but that it is too low and we reach it" (c) Michelangelo
>
>
Gdon't know if the best but you cant ry something along the line of
Gprivate static Rage _isNumber = new Rage(@"^\d+$");
Gpublic static bool IsInteger(strin g theValue)
G{
GMatch m = _isNumber.Match (theValue);
Greturn m.Success;
G} //IsInteger
>
>

[tshad]

Re: Best way to check if string is numeric

"Michael Nemtsev [MVP]" <nemtsev@msn.co mwrote in message
news:3d9fba1a20 e7e8ca0fbe373aa 890@msnews.micr osoft.com...

Hello GS,
>
"If u have a promblem an gonna solve it with RegExp then now u have two
problems"

Why is RegExp a problem?

Thanks,

tom

(c) dont remember who
>
---
WBR, Michael Nemtsev [.NET/C# MVP] :: blog:

http://spaces.live.com/laflour

"The greatest danger for most of us is not that our aim is too high and we
miss it, but that it is too low and we reach it" (c) Michelangelo
>
Gdon't know if the best but you cant ry something along the line of
Gprivate static Rage _isNumber = new Rage(@"^\d+$");
Gpublic static bool IsInteger(strin g theValue)
G{
GMatch m = _isNumber.Match (theValue);
Greturn m.Success;
G} //IsInteger
>
>

[Jon Skeet [C# MVP]]

Re: Best way to check if string is numeric

On Dec 18, 4:15 pm, "tshad" <t...@dslextrem e.comwrote:

"If u have a promblem an gonna solve it with RegExp then now u have two
problems"

>
Why is RegExp a problem?

When it's used in a "hammer to crack a nut" sense, it produces far
less maintainable code.
For genuine pattern matching, it's fine - but often there's a simpler
alternative.

It's very easy to get things wrong, regular expressions vary between
different platforms (and indeed between different versions of .NET),
you have to bear in mind escaping, etc.

Jon

[=?Utf-8?B?UGV0ZXIgQnJvbWJlcmcgW0MjIE1WUF0=?=]

RE: Best way to check if string is numeric

in the Microsoft.Visua lBasic namespace, there is a very complete
implementation of IsNumeric. Of course, you may not need or even want such a
"feature rich" implementation, but you could take a look.
-- Peter
Site: http://www.eggheadcafe.com
UnBlog: http://petesbloggerama.blogspot.com
MetaFinder: http://www.blogmetafinder.com


"tshad" wrote:

I have a string field and a decimal fields and was wondering what the best
way to check for numeric is?
>
I have to do something like:
>
If (myAmount is numeric)
{
total += myAmount;
}
>
Thanks,
>
Tom
>
>
>

[Paul E Collins]

Re: Best way to check if string is numeric

"GS" <gsmsnews.micro soft.comGS@msne ws.Nomail.comwr ote:

[regular expression for matching numbers]

- Doesn't handle negative numbers.
- Even if it did, might not handle foreign variations (e.g. symbol for
negative that isn't "-").
- Will match *long* strings of digits that are bigger than an integer
can store.

Int32.TryParse is a lot safer.

Eq.

[Greg]

Re: Best way to check if string is numeric

On Dec 17, 10:02 pm, "tshad" <t...@dslextrem e.comwrote:

I have a string field and a decimal fields and was wondering what the best
way to check for numeric is?
>
I have to do something like:
>
If (myAmount is numeric)
{
total += myAmount;
>
}
>
Thanks,
>
Tom

Tom,

Another approach (depending on your parsing needs) is to take a look
at an extended TextBox that deals specifically with numeric data. The
source code is small for this control.

How to: Create a Numeric Text Box

http://msdn2.microsoft.com/en-us/library/ms229644.aspx

HTH

Greg

[Kalpesh]

Re: Best way to check if string is numeric

tshad,

Isn't Parse or TryParse a simple thing to do in this case?
MVPs can suggest better ways, if this doesn't help

Kalpesh

[Ben Voigt [C++ MVP]]

Re: Best way to check if string is numeric


"Kalpesh" <shahkalpesh@gm ail.comwrote in message
news:75d2df7b-f384-4d22-a348-f5439971a017@e1 0g2000prf.googl egroups.com...

tshad,
>
Isn't Parse or TryParse a simple thing to do in this case?
MVPs can suggest better ways, if this doesn't help

Parse or TryParse is in fact mandatory, because even if the string is a
numeric sequence of digits, you still can't use it for math. You *have* to
parse it into a proper numeric variable first.

>
Kalpesh

[Jon Skeet [C# MVP]]

Re: Best way to check if string is numeric

Ben Voigt [C++ MVP] <rbv@nospam.nos pamwrote:

Isn't Parse or TryParse a simple thing to do in this case?
MVPs can suggest better ways, if this doesn't help

>
Parse or TryParse is in fact mandatory, because even if the string is a
numeric sequence of digits, you still can't use it for math. You *have* to
parse it into a proper numeric variable first.

While that's true, sometimes only validation is required. For instance,
it's reasonably common in web applications to require some client-side
validation that the user has typed in a number, but not to actually
have to *deal* with it as a number until it reaches the server.

--
Jon Skeet - <skeet@pobox.co m>
http://www.pobox.com/~skeet Blog: http://www.msmvps.com/jon.skeet
World class .NET training in the UK: http://iterativetraining.co.uk

[Ben Voigt [C++ MVP]]

Re: Best way to check if string is numeric


"Jon Skeet [C# MVP]" <skeet@pobox.co mwrote in message
news:MPG.21dc90 2ee31f83373e@ms news.microsoft. com...

Ben Voigt [C++ MVP] <rbv@nospam.nos pamwrote:

Isn't Parse or TryParse a simple thing to do in this case?
MVPs can suggest better ways, if this doesn't help

>>
>Parse or TryParse is in fact mandatory, because even if the string is a
>numeric sequence of digits, you still can't use it for math. You *have*
>to
>parse it into a proper numeric variable first.

>
While that's true, sometimes only validation is required. For instance,
it's reasonably common in web applications to require some client-side
validation that the user has typed in a number, but not to actually
have to *deal* with it as a number until it reaches the server.

The OP said

<quote>
I have to do something like:

If (myAmount is numeric)
{
total += myAmount;
}
</quote>

>
--
Jon Skeet - <skeet@pobox.co m>
http://www.pobox.com/~skeet Blog: http://www.msmvps.com/jon.skeet
World class .NET training in the UK: http://iterativetraining.co.uk