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  4. Working with value pairs(a key and a value)

Working with value pairs(a key and a value)

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  • C Offline
    C Offline
    CodingLover
    wrote on last edited by
    #1

    Hi all, I want to save pair of values, a key and a related value of it. I use HashTable to store them as follows. private System.Collections.Hashtable hshTable = new System.Collections.Hashtable(); hshTable.Add("One", 1); hshTable.Add("Two", 2); hshTable.Add("Three", 3); hshTable.Add("One", 6); Check that last line, I cannot do that. Actually what I want to do is, on existing entry value should be updated. How can I solve this problem. Thanks :)

    I appreciate your help all the time... CodingLover :)

    G L N T B 7 Replies Last reply
    0
    • C CodingLover

      Hi all, I want to save pair of values, a key and a related value of it. I use HashTable to store them as follows. private System.Collections.Hashtable hshTable = new System.Collections.Hashtable(); hshTable.Add("One", 1); hshTable.Add("Two", 2); hshTable.Add("Three", 3); hshTable.Add("One", 6); Check that last line, I cannot do that. Actually what I want to do is, on existing entry value should be updated. How can I solve this problem. Thanks :)

      I appreciate your help all the time... CodingLover :)

      G Offline
      G Offline
      Giorgi Dalakishvili
      wrote on last edited by
      #2

      hshTable["One"] = 6 If there is no item with key "One" new item will be added. If there is, old value will be overwritten.

      Giorgi Dalakishvili #region signature My Articles Asynchronous Registry Notification Using Strongly-typed WMI Classes in .NET [^] My blog #endregion

      1 Reply Last reply
      0
      • C CodingLover

        Hi all, I want to save pair of values, a key and a related value of it. I use HashTable to store them as follows. private System.Collections.Hashtable hshTable = new System.Collections.Hashtable(); hshTable.Add("One", 1); hshTable.Add("Two", 2); hshTable.Add("Three", 3); hshTable.Add("One", 6); Check that last line, I cannot do that. Actually what I want to do is, on existing entry value should be updated. How can I solve this problem. Thanks :)

        I appreciate your help all the time... CodingLover :)

        L Offline
        L Offline
        Luc Pattyn
        wrote on last edited by
        #3

        Hi, you can also call Hashtable.Remove(key) before calling Hashtable.Add(key,val); there is no need to test for existence first. The same principle applies to the generic Dictionary<T> class. BTW:And it is similar to removing-then-adding a delegate to an event. :)

        Luc Pattyn [Forum Guidelines] [My Articles]


        Fixturized forever. :confused:


        C 1 Reply Last reply
        0
        • C CodingLover

          Hi all, I want to save pair of values, a key and a related value of it. I use HashTable to store them as follows. private System.Collections.Hashtable hshTable = new System.Collections.Hashtable(); hshTable.Add("One", 1); hshTable.Add("Two", 2); hshTable.Add("Three", 3); hshTable.Add("One", 6); Check that last line, I cannot do that. Actually what I want to do is, on existing entry value should be updated. How can I solve this problem. Thanks :)

          I appreciate your help all the time... CodingLover :)

          N Offline
          N Offline
          N a v a n e e t h
          wrote on last edited by
          #4

          Use a generic Dictionary(TKey,TValue). It has a ContainsKey method which will return TRUE if the key supplied exists. If it exist, just update the value instead of adding new one.

          1 Reply Last reply
          0
          • L Luc Pattyn

            Hi, you can also call Hashtable.Remove(key) before calling Hashtable.Add(key,val); there is no need to test for existence first. The same principle applies to the generic Dictionary<T> class. BTW:And it is similar to removing-then-adding a delegate to an event. :)

            Luc Pattyn [Forum Guidelines] [My Articles]


            Fixturized forever. :confused:


            C Offline
            C Offline
            CodingLover
            wrote on last edited by
            #5

            Thanks for replays. Actually I got data pair like One 2 and so on. I want to store each of them. If I found a duplicate one value(number) should be updated. Then later I want to take all of them to make a string. Say my data like this. One 3 Two 5 One 7 Then the string should be, One 7 Two 5

            I appreciate your help all the time... CodingLover :)

            L 1 Reply Last reply
            0
            • C CodingLover

              Hi all, I want to save pair of values, a key and a related value of it. I use HashTable to store them as follows. private System.Collections.Hashtable hshTable = new System.Collections.Hashtable(); hshTable.Add("One", 1); hshTable.Add("Two", 2); hshTable.Add("Three", 3); hshTable.Add("One", 6); Check that last line, I cannot do that. Actually what I want to do is, on existing entry value should be updated. How can I solve this problem. Thanks :)

              I appreciate your help all the time... CodingLover :)

              T Offline
              T Offline
              TJS4u
              wrote on last edited by
              #6

              hello How can u think of storing the different value with the same "Key" As u mentioned "One"====> the key ... how it can be repeated under the same instance see link http://www.c-sharpcorner.com/UploadFile/mahesh/Hashtable11082005171748PM/Hashtable.aspx?ArticleID=6880f0d4-acc6-402c-b632-d2e353e98e62

              1 Reply Last reply
              0
              • C CodingLover

                Hi all, I want to save pair of values, a key and a related value of it. I use HashTable to store them as follows. private System.Collections.Hashtable hshTable = new System.Collections.Hashtable(); hshTable.Add("One", 1); hshTable.Add("Two", 2); hshTable.Add("Three", 3); hshTable.Add("One", 6); Check that last line, I cannot do that. Actually what I want to do is, on existing entry value should be updated. How can I solve this problem. Thanks :)

                I appreciate your help all the time... CodingLover :)

                B Offline
                B Offline
                Brij
                wrote on last edited by
                #7

                Make a custom function for it which check whether this entry is already there or not by hshTable.ContainsKey("one") if it there then remove it as hshTable.Remove("one"); and again add as hshTable.Add("One", 6);

                Cheers!! Brij

                L 1 Reply Last reply
                0
                • B Brij

                  Make a custom function for it which check whether this entry is already there or not by hshTable.ContainsKey("one") if it there then remove it as hshTable.Remove("one"); and again add as hshTable.Add("One", 6);

                  Cheers!! Brij

                  L Offline
                  L Offline
                  Luc Pattyn
                  wrote on last edited by
                  #8

                  Hi, create a 5-line method to do what a single statement can do? I suggest you (re)read Giorgi's and my earlier replies. :)

                  Luc Pattyn [Forum Guidelines] [My Articles]


                  Fixturized forever. :confused:


                  1 Reply Last reply
                  0
                  • C CodingLover

                    Thanks for replays. Actually I got data pair like One 2 and so on. I want to store each of them. If I found a duplicate one value(number) should be updated. Then later I want to take all of them to make a string. Say my data like this. One 3 Two 5 One 7 Then the string should be, One 7 Two 5

                    I appreciate your help all the time... CodingLover :)

                    L Offline
                    L Offline
                    Luc Pattyn
                    wrote on last edited by
                    #9

                    Hi, you can add/replace key-value pairs as shown before. for a Dictionary<(TKey, TValue> you can enumerate all keys with foreach(TKey key in Dictionary.Keys) {...} and similar stuff goes for old Hashtables. WARNING: dictionaries, hashtables don't preserve chronology, so there is no guarantee that "One 2" will come first in the enumeration. If you insist on having that, you will need a different approach, most likely a combination of a List and a Dictionary (a List preserves order unless you instruct it to drop the order, e.g. by sorting). :)

                    Luc Pattyn [Forum Guidelines] [My Articles]


                    Fixturized forever. :confused:


                    1 Reply Last reply
                    0
                    • C CodingLover

                      Hi all, I want to save pair of values, a key and a related value of it. I use HashTable to store them as follows. private System.Collections.Hashtable hshTable = new System.Collections.Hashtable(); hshTable.Add("One", 1); hshTable.Add("Two", 2); hshTable.Add("Three", 3); hshTable.Add("One", 6); Check that last line, I cannot do that. Actually what I want to do is, on existing entry value should be updated. How can I solve this problem. Thanks :)

                      I appreciate your help all the time... CodingLover :)

                      N Offline
                      N Offline
                      Navneet Hegde
                      wrote on last edited by
                      #10

                      Hi! It quite simple If Key Not Exists Keep on Adding Else If Exists RemoveKey and then Add Thanks!

                      Develop2Program & Program2Develop

                      T 1 Reply Last reply
                      0
                      • N Navneet Hegde

                        Hi! It quite simple If Key Not Exists Keep on Adding Else If Exists RemoveKey and then Add Thanks!

                        Develop2Program & Program2Develop

                        T Offline
                        T Offline
                        TJS4u
                        wrote on last edited by
                        #11

                        ohhhhhhh wht an answer u ..... made out .......... hoooooooooooo fantastic :laugh:

                        N 1 Reply Last reply
                        0
                        • T TJS4u

                          ohhhhhhh wht an answer u ..... made out .......... hoooooooooooo fantastic :laugh:

                          N Offline
                          N Offline
                          Navneet Hegde
                          wrote on last edited by
                          #12

                          ok

                          Develop2Program & Program2Develop

                          T 1 Reply Last reply
                          0
                          • C CodingLover

                            Hi all, I want to save pair of values, a key and a related value of it. I use HashTable to store them as follows. private System.Collections.Hashtable hshTable = new System.Collections.Hashtable(); hshTable.Add("One", 1); hshTable.Add("Two", 2); hshTable.Add("Three", 3); hshTable.Add("One", 6); Check that last line, I cannot do that. Actually what I want to do is, on existing entry value should be updated. How can I solve this problem. Thanks :)

                            I appreciate your help all the time... CodingLover :)

                            S Offline
                            S Offline
                            Seraph_summer
                            wrote on last edited by
                            #13

                            I think it is easy to solve your problem with many ways: e.g: use the combination of your key and value as new key;

                            1 Reply Last reply
                            0
                            • N Navneet Hegde

                              ok

                              Develop2Program & Program2Develop

                              T Offline
                              T Offline
                              TJS4u
                              wrote on last edited by
                              #14

                              OK Program2Develop & Develop2Program

                              1 Reply Last reply
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