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String to int

Scheduled Pinned Locked Moved C#
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  • M Offline
    M Offline
    mrithula8
    wrote on last edited by
    #1

    Hi can i convert a string to integer variable in C#?If so can you please tell me.I have given the port number <port>10000<port> in an xml file .I want to read this number from xml and assign to int variable so that it can be passed to the IPEndPoint() for client/server commnuication.Whatever i read from xml is retrieved as string.I tried with ConvertToInt() but still im not getting.Can you please explain me the reason?

    M D 2 Replies Last reply
    0
    • M mrithula8

      Hi can i convert a string to integer variable in C#?If so can you please tell me.I have given the port number <port>10000<port> in an xml file .I want to read this number from xml and assign to int variable so that it can be passed to the IPEndPoint() for client/server commnuication.Whatever i read from xml is retrieved as string.I tried with ConvertToInt() but still im not getting.Can you please explain me the reason?

      M Offline
      M Offline
      musefan
      wrote on last edited by
      #2

      int result; int.TryParse("10000", out result);

      Life goes very fast. Tomorrow, today is already yesterday.

      M 1 Reply Last reply
      0
      • M mrithula8

        Hi can i convert a string to integer variable in C#?If so can you please tell me.I have given the port number <port>10000<port> in an xml file .I want to read this number from xml and assign to int variable so that it can be passed to the IPEndPoint() for client/server commnuication.Whatever i read from xml is retrieved as string.I tried with ConvertToInt() but still im not getting.Can you please explain me the reason?

        D Offline
        D Offline
        DaveyM69
        wrote on last edited by
        #3

        musefan has given you the perfect answer. Just be aware that if the number can't be converted to an int you will get zero. I have an extension method that I use when working with text/xml etc files to simplify stuff.

        public static class ExtensionMethods
        {
        /// <summary>
        /// Converts a string to an integer.
        /// </summary>
        /// <param name="value">The string to convert.</param>
        /// <returns>The integer value of the string if valid; otherwise, zero.</returns>
        public static Int32 ToInt32(this string value)
        {
        int result;
        Int32.TryParse(value, out result);
        return result;
        }
        }

        Now I can can just use something like

        int intFromFile = stringFromFile.ToInt32();

        Dave
        BTW, in software, hope and pray is not a viable strategy. (Luc Pattyn)
        Visual Basic is not used by normal people so we're not covering it here. (Uncyclopedia)

        G 1 Reply Last reply
        0
        • M musefan

          int result; int.TryParse("10000", out result);

          Life goes very fast. Tomorrow, today is already yesterday.

          M Offline
          M Offline
          Michael Bookatz
          wrote on last edited by
          #4

          what's the difference between the method you've used and result = int.parse("100000");

          M M M 3 Replies Last reply
          0
          • D DaveyM69

            musefan has given you the perfect answer. Just be aware that if the number can't be converted to an int you will get zero. I have an extension method that I use when working with text/xml etc files to simplify stuff.

            public static class ExtensionMethods
            {
            /// <summary>
            /// Converts a string to an integer.
            /// </summary>
            /// <param name="value">The string to convert.</param>
            /// <returns>The integer value of the string if valid; otherwise, zero.</returns>
            public static Int32 ToInt32(this string value)
            {
            int result;
            Int32.TryParse(value, out result);
            return result;
            }
            }

            Now I can can just use something like

            int intFromFile = stringFromFile.ToInt32();

            Dave
            BTW, in software, hope and pray is not a viable strategy. (Luc Pattyn)
            Visual Basic is not used by normal people so we're not covering it here. (Uncyclopedia)

            G Offline
            G Offline
            Greg Chelstowski
            wrote on last edited by
            #5

            If I might... Is it considered really bad practice to do Convert.ToInt32 ? I have seen stuff (and well, I have used it, too) like:

            string x = "10";
            int xInt;
            try
            {
            xInt = Convert.ToInt32(x);
            }
            catch
            {
            xInt = 0;
            }

            Would that not do the same as TryParse? Or is it an unnecessary way around it, or simply, crap?

            var question = (_2b || !(_2b));

            D 1 Reply Last reply
            0
            • M Michael Bookatz

              what's the difference between the method you've used and result = int.parse("100000");

              M Offline
              M Offline
              Mohammad Dayyan
              wrote on last edited by
              #6

              there is no difference

              1 Reply Last reply
              0
              • M Michael Bookatz

                what's the difference between the method you've used and result = int.parse("100000");

                M Offline
                M Offline
                musefan
                wrote on last edited by
                #7

                The difference is that if you pass a string to int.parse() that is not a valid string (contains noon-numeric characters) it will throw an exception that you will need to manually handle. If you use my method the error is handled automatically and the result is set to 0, its up to you if you want to handle the error yourself thou, depends how much validation control you need. if you are expecting the result could sometimes be 0 as a result then you may be best to handle the error yourself. but in the case of a port number you shouldnt need to do this, just check if result is 0 for an error.

                Life goes very fast. Tomorrow, today is already yesterday.

                M D 2 Replies Last reply
                0
                • M Michael Bookatz

                  what's the difference between the method you've used and result = int.parse("100000");

                  M Offline
                  M Offline
                  Mirko1980
                  wrote on last edited by
                  #8

                  If the input string is not a valid integer, int.Parse throws an exception, while int.TryParse returns false without setting result value. e.g.

                  string wrong = "xyz";
                  result = int.Parse(wrong); // an exception is thrown here

                  string wrong = "xyz";
                  int result = -1;
                  bool success = int.TryParse(wrong, out result); // success is false, while result will still be -1

                  M 1 Reply Last reply
                  0
                  • M musefan

                    The difference is that if you pass a string to int.parse() that is not a valid string (contains noon-numeric characters) it will throw an exception that you will need to manually handle. If you use my method the error is handled automatically and the result is set to 0, its up to you if you want to handle the error yourself thou, depends how much validation control you need. if you are expecting the result could sometimes be 0 as a result then you may be best to handle the error yourself. but in the case of a port number you shouldnt need to do this, just check if result is 0 for an error.

                    Life goes very fast. Tomorrow, today is already yesterday.

                    M Offline
                    M Offline
                    Michael Bookatz
                    wrote on last edited by
                    #9

                    Thank you for the reply... next time I convert I'll bare it in mind.

                    1 Reply Last reply
                    0
                    • M Mirko1980

                      If the input string is not a valid integer, int.Parse throws an exception, while int.TryParse returns false without setting result value. e.g.

                      string wrong = "xyz";
                      result = int.Parse(wrong); // an exception is thrown here

                      string wrong = "xyz";
                      int result = -1;
                      bool success = int.TryParse(wrong, out result); // success is false, while result will still be -1

                      M Offline
                      M Offline
                      Michael Bookatz
                      wrote on last edited by
                      #10

                      Thanks for the reply, however according to the above post the result would be set to zero and not stay at -1 or is it only set to zero if there is no valid number in it?

                      M D 2 Replies Last reply
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                      • M Michael Bookatz

                        Thanks for the reply, however according to the above post the result would be set to zero and not stay at -1 or is it only set to zero if there is no valid number in it?

                        M Offline
                        M Offline
                        Mirko1980
                        wrote on last edited by
                        #11

                        Yes, I was wrong, int.TryParse puts 0 in the result if the parsing fails. For some reason, I tought that the resul value was unchanged in case of failure, my bad.

                        M 1 Reply Last reply
                        0
                        • M musefan

                          The difference is that if you pass a string to int.parse() that is not a valid string (contains noon-numeric characters) it will throw an exception that you will need to manually handle. If you use my method the error is handled automatically and the result is set to 0, its up to you if you want to handle the error yourself thou, depends how much validation control you need. if you are expecting the result could sometimes be 0 as a result then you may be best to handle the error yourself. but in the case of a port number you shouldnt need to do this, just check if result is 0 for an error.

                          Life goes very fast. Tomorrow, today is already yesterday.

                          D Offline
                          D Offline
                          DaveyM69
                          wrote on last edited by
                          #12

                          musefan wrote:

                          just check if result is 0 for an error

                          Better to assign and check the boolean return value of the TryParse method before working with the value. Still preferable to catching an exception!

                          Dave
                          BTW, in software, hope and pray is not a viable strategy. (Luc Pattyn)
                          Visual Basic is not used by normal people so we're not covering it here. (Uncyclopedia)

                          M 1 Reply Last reply
                          0
                          • M Mirko1980

                            Yes, I was wrong, int.TryParse puts 0 in the result if the parsing fails. For some reason, I tought that the resul value was unchanged in case of failure, my bad.

                            M Offline
                            M Offline
                            Michael Bookatz
                            wrote on last edited by
                            #13

                            No worries thanks for the clarification

                            1 Reply Last reply
                            0
                            • M Michael Bookatz

                              Thanks for the reply, however according to the above post the result would be set to zero and not stay at -1 or is it only set to zero if there is no valid number in it?

                              D Offline
                              D Offline
                              DaveyM69
                              wrote on last edited by
                              #14

                              hopingToCode wrote:

                              only set to zero if there is no valid number

                              ... or if the number in the text is zero! Check the return value of the TryParse method to determine if successful.

                              Dave
                              BTW, in software, hope and pray is not a viable strategy. (Luc Pattyn)
                              Visual Basic is not used by normal people so we're not covering it here. (Uncyclopedia)

                              1 Reply Last reply
                              0
                              • D DaveyM69

                                musefan wrote:

                                just check if result is 0 for an error

                                Better to assign and check the boolean return value of the TryParse method before working with the value. Still preferable to catching an exception!

                                Dave
                                BTW, in software, hope and pray is not a viable strategy. (Luc Pattyn)
                                Visual Basic is not used by normal people so we're not covering it here. (Uncyclopedia)

                                M Offline
                                M Offline
                                musefan
                                wrote on last edited by
                                #15

                                Ahh yes, i forgot TryParse() returns a bool

                                Life goes very fast. Tomorrow, today is already yesterday.

                                1 Reply Last reply
                                0
                                • G Greg Chelstowski

                                  If I might... Is it considered really bad practice to do Convert.ToInt32 ? I have seen stuff (and well, I have used it, too) like:

                                  string x = "10";
                                  int xInt;
                                  try
                                  {
                                  xInt = Convert.ToInt32(x);
                                  }
                                  catch
                                  {
                                  xInt = 0;
                                  }

                                  Would that not do the same as TryParse? Or is it an unnecessary way around it, or simply, crap?

                                  var question = (_2b || !(_2b));

                                  D Offline
                                  D Offline
                                  DaveyM69
                                  wrote on last edited by
                                  #16

                                  Not bad practice, possibly a little slower going via the Convert class but I would have to check the implementation to be sure. The convert class is great for converting from a built in type to another (not just from string), but I would guess the Int32.Parse or Int32.TryParse methods would be perhaps a little more efficient.

                                  Dave
                                  BTW, in software, hope and pray is not a viable strategy. (Luc Pattyn)
                                  Visual Basic is not used by normal people so we're not covering it here. (Uncyclopedia)

                                  1 Reply Last reply
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