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isnumeric in c#

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  • A Amar Chaudhary

    nice and should include 43 and 45 also :):)

    It is Good to be Important but! it is more Important to be Good

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    rah_sin
    wrote on last edited by
    #6

    u can try private bool IsNumeric(object numberString) { string strVal = numberString.ToString(); char [] ca = strVal.ToCharArray(); for (int i = 0; i < ca.Length;i++) { if (Char.IsNumber(ca[i])) return false; else return true; } }

    rahul

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    • A Amar Chaudhary

      but these meathods through exceptions which is a lag in performance :):)

      It is Good to be Important but! it is more Important to be Good

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      Martin 0
      wrote on last edited by
      #7

      Hello,

      Amar Chaudhary wrote:

      these meathods through exceptions

      No, thats not true. That's the differents between 'Parse' and 'Convert.ToInt32'. If it's possible for you you should use 'TryParse' in an 'if' == true statement. All the best, Martin

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      • R rah_sin

        u can try private bool IsNumeric(object numberString) { string strVal = numberString.ToString(); char [] ca = strVal.ToCharArray(); for (int i = 0; i < ca.Length;i++) { if (Char.IsNumber(ca[i])) return false; else return true; } }

        rahul

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        ejuanpp
        wrote on last edited by
        #8

        Ithink you just check ca[0]

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        • R rah_sin

          u can try private bool IsNumeric(object numberString) { string strVal = numberString.ToString(); char [] ca = strVal.ToCharArray(); for (int i = 0; i < ca.Length;i++) { if (Char.IsNumber(ca[i])) return false; else return true; } }

          rahul

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          RanjithLogics
          wrote on last edited by
          #9

          gr8 Rahul

          Ranjith Stephen

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          • R RanjithLogics

            gr8 Rahul

            Ranjith Stephen

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            J4amieC
            wrote on last edited by
            #10

            ranjithlogics wrote:

            gr8 Rahul

            Yes "gr8" indeed :rolleyes: as in reading this makes me want to gr8 my forehead with a cheese gr8er. Specifically if (Char.IsNumber(ca[i])) return false; within a method called IsNumeric - whose purpose is to return true when a string is numeric.

            --- How to get answers to your questions[^]

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            • R rah_sin

              u can try private bool IsNumeric(object numberString) { string strVal = numberString.ToString(); char [] ca = strVal.ToCharArray(); for (int i = 0; i < ca.Length;i++) { if (Char.IsNumber(ca[i])) return false; else return true; } }

              rahul

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              J4amieC
              wrote on last edited by
              #11

              rah_sin wrote:

              for (int i = 0; i < ca.Length;i++) { if (Char.IsNumber(ca[i])) return false; else return true; }

              This logic is so badly flawed.. 1) false is returned if a character is numeric - the purpose of the method was supposed to be returning true if a caracter is numeric 2) It always returns on the first character, rather than checking the whole string is made up of numbers... basically the for loop is useless.

              --- How to get answers to your questions[^]

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              • A Amar Chaudhary

                how can we use isnumeric in c# thanks :):)

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                J4amieC
                wrote on last edited by
                #12

                As has been hinted, rather badly, by previous posters the way to write an isnumeric method is to iterate over each character in a string checking whether Char.IsNumber is true or char == '.' for every character in the string. You may want to remove formatting from the number, as often numbers may be separated with a comma (1,000,000) and sometimes numbers are a representation of currency (£100) - you may or may not want these two cases to be treated as valid numerics.

                --- How to get answers to your questions[^]

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                • J J4amieC

                  As has been hinted, rather badly, by previous posters the way to write an isnumeric method is to iterate over each character in a string checking whether Char.IsNumber is true or char == '.' for every character in the string. You may want to remove formatting from the number, as often numbers may be separated with a comma (1,000,000) and sometimes numbers are a representation of currency (£100) - you may or may not want these two cases to be treated as valid numerics.

                  --- How to get answers to your questions[^]

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                  Dan Neely
                  wrote on last edited by
                  #13

                  J4amieC wrote:

                  As has been hinted, rather badly, by previous posters the way to write an isnumeric method is to iterate over each character in a string checking whether Char.IsNumber is true or char == '.' for every character in the string.

                  You also need to check for '-' in the first char, and that '.' only appears once.

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                  • A Amar Chaudhary

                    but these meathods through exceptions which is a lag in performance :):)

                    It is Good to be Important but! it is more Important to be Good

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                    Ennis Ray Lynch Jr
                    wrote on last edited by
                    #14

                    I really doubt MS would implement it as such but I would really like to see documentation on the way Int32.TryParse was implemented just so I can see for myself. I suppose, if I wasn't so lazy I could just look at the MSIL ... actually I think I am about to do that.


                    On two occasions I have been asked [by members of Parliament], 'Pray, Mr. Babbage, if you put into the machine wrong figures, will the right answers come out?' I am not able rightly to apprehend the kind of confusion of ideas that could provoke such a question. - Charles Babbage

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                    • E Ennis Ray Lynch Jr

                      I really doubt MS would implement it as such but I would really like to see documentation on the way Int32.TryParse was implemented just so I can see for myself. I suppose, if I wasn't so lazy I could just look at the MSIL ... actually I think I am about to do that.


                      On two occasions I have been asked [by members of Parliament], 'Pray, Mr. Babbage, if you put into the machine wrong figures, will the right answers come out?' I am not able rightly to apprehend the kind of confusion of ideas that could provoke such a question. - Charles Babbage

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                      Ennis Ray Lynch Jr
                      wrote on last edited by
                      #15

                      No try catch. I would post a snippet but it is way long. Int32.TryParse traces all the way up to Number.ParseNumber.


                      On two occasions I have been asked [by members of Parliament], 'Pray, Mr. Babbage, if you put into the machine wrong figures, will the right answers come out?' I am not able rightly to apprehend the kind of confusion of ideas that could provoke such a question. - Charles Babbage

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                      • J J4amieC

                        rah_sin wrote:

                        for (int i = 0; i < ca.Length;i++) { if (Char.IsNumber(ca[i])) return false; else return true; }

                        This logic is so badly flawed.. 1) false is returned if a character is numeric - the purpose of the method was supposed to be returning true if a caracter is numeric 2) It always returns on the first character, rather than checking the whole string is made up of numbers... basically the for loop is useless.

                        --- How to get answers to your questions[^]

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                        rah_sin
                        wrote on last edited by
                        #16

                        my aim was not to write codes for u rather to suggest the method Char.IsNumber(); now its upto u that how can u use it for ur purpose i think u people are smart enough to write ur ownn logics.

                        rahul

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