Check string is numeric by using try parse in c#

Question

I have value as belowbelow

string value = "10053409434400003333336533210923";

When I try to parse below it isNumeric displays always false result because of long (i think)

long n;
bool isNumeric = long.TryParse(value , out n);
if (!isNumeric) // Always false
{

}

Where I miss in code how can I check string (even 50 characters) value is numeric or not ?

Thanks

Your code and your question shows/tells different things. Your code try to parse your string to long which returns false because your value is too big for long type. Your question says; how can I check string value is numeric which I guess you try to check every character is numeric or not which is already have a question. Can you please clarify your question? — Soner Gönül
– Soner Gönül, Commented Apr 30, 2015 at 7:32
You also didn't say whether you want to allow a negative value. The LINQ and regex methods in the answers will fail to recognize that. — Dirk
– Dirk, Commented Apr 30, 2015 at 7:34
Parsing does even more job than simply going through string character by character. Your solution to the problem is similar to one when you convert int x to string and test its Lengh to see if x > 9 && x < 100. Correct approach is given by @AlexD answer. — Sinatr
– Sinatr, Commented Apr 30, 2015 at 7:39

AlexD · Accepted Answer · 2015-04-30 07:31:10Z

13

If you want to check if all characters are digits, without making sure that the number can be represented by an integral type, try Linq:

bool digitsOnly = s.All(c => char.IsDigit(c));

answered Apr 30, 2015 at 7:31

AlexD

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Comments

Mitch Wheat · Accepted Answer · 2015-04-30 07:38:04Z

6

If you want to be able to use the parsed number, you will need a type large enough to represent it. A .NET long can support –9,223,372,036,854,775,808 to 9,223,372,036,854,775,807 so I suggest using BigInteger (add a reference to System.Numerics)

BigInteger number1;
bool succeeded1 = BigInteger.TryParse("10053409434400003333336533210923", out number1);

BigInteger.TryParse

edited Apr 30, 2015 at 7:38

answered Apr 30, 2015 at 7:32

Mitch Wheat

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2 Comments

Georg Over a year ago

You will need a reference to System.Numerics for this to work.

Richard Over a year ago

yes you are right that's my fault but your code is ok thanks for help

Community · Accepted Answer · 2017-05-23 10:28:27Z

2

You can try this solution : https://stackoverflow.com/a/894567/1793453

Regex.IsMatch(input, @"^\d+$")

edited May 23, 2017 at 10:28

CommunityBot

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answered Apr 30, 2015 at 7:33

Edward N

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Comments

BaBu · Accepted Answer · 2015-04-30 07:35:16Z

2

The long type is 64 bit and can only hold values from –9223372036854775808 to 9223372036854775807.

You could use a Regex instead:

Regex regex = new Regex(@"^\d+$");

answered Apr 30, 2015 at 7:35

BaBu

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