comparing values in 2 Hash tables

Question

Hello everyone!
I'm trying to compare values in 2 hash tables based on the same keys. So for example, I have a set a as follows:
hashtable1 (123, "apple"), hashtable1(234, "tree"), etc.
hashtable2 (123, "orange"), hashtable2(234, "tree")
So I need to loop through all the items in both hashtables, and compare the values, whenever the values are different, I need to print them out. And then, if the number of items is different, for example, hashtable1 has a couple of more keys, that are not in hashtable2, I need to print out what's different. I'm pretty new to C#, and cannot seem to quite find the syntax on how to do it. I'd appreciate any help. thank you!

Sam Hobbs · Answer

I am an old programmer that has written many programs that match two files such as matching transaction and a master file to apply updates. Young programmers seldom need to do that. The following will match the two tables in the sense that it iterates through each table together to find mismatches. Note that I first put each hash table into a SortedList because the data must be sorted for this to work. I am using other tricks that I hope you are able to understand. Note also that I am assuming that the keys are integers; if not then I hope you are able to modify this code appropriately. Also note that if it were me I would use generic collections and if you do then I hope you can modify this code appropriately for that. SortedList sl1 = new SortedList(ht1); SortedList sl2 = new SortedList(ht2); int x1 = 0; int x2 = 0; IList kl1 = sl1.GetKeyList(); IList kl2 = sl2.GetKeyList(); int k1 = 0; int k2 = 0; while (x1 { k1 = x1 k2 = x2 if (k1 == k2) { if (sl1[k1] == sl2[k2]) Console.WriteLine({0} equal k1); else Console.WriteLine({0} not equal {1} {2} k1 sl1[k1] sl2[k2]); ++x1; ++x2; } else if (k1 { Console.WriteLine({0} not in second k1); ++x1; } else { Console.WriteLine({0} not in first k2); ++x2; } }

vi M · Answer

Sam Hobbs - thank you for your help! No there won't be any items in the second table that are not in the first. One table always will have the correct data and I just need to see if the data in the other one is different. I'll play with it some more and will try your solution if I can't make mine work. Thanks again.

Sam Hobbs · Answer

I gave you the best I have to offer. Note that in my code the line that writes the data that are equal is there for diagnostic purposes; I hope you understand how to remove it so there is no output when the data is equal. Will there ever be items in the second table that are not in the first? Your code won't find them.

vi M · Answer

I actually made this code work by making the following changes below. The only thing I can't figure is how to make it print only once ( right now it prints as many times as there items in the the DictionaryEntry). System.Collections.Hashtable a = new System.Collections.Hashtable(); System.Collections.Hashtable ht2 = new System.Collections.Hashtable(); ***code to populate the hashtables*** Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:Table Normal; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:Calibrisans-serif; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:Times New Roman; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin;} foreach (System.Collections. DictionaryEntry de in a) { foreach (System.Collections. DictionaryEntry de2 in ht2) { if (ht2.ContainsKey(de.Key) && !ht2[de.Key].Equals(a[de.Key]) ) { Results.Items.Add( This file has been changed + de.Key); } } }

vi M · Answer

Jitendra - thank you thank you! The code worked just perfect. I also need to do the comparison if the keys are the same but their values are different I need to print out the result too. Right now I have the following code but it doesn't seem to be working right: System.Collections.Hashtable a = new System.Collections.Hashtable(); System.Collections.Hashtable ht2 = new System.Collections.Hashtable(); ***code to populate the hashtables*** foreach (System.Collections.DictionaryEntry de in a) { Results.Items.Add(Value in de: + de.Value + Key in de: + de.Key); foreach (System.Collections.DictionaryEntry de2 in ht2) { Results.Items.Add(Value in de2: + de2.Value + Key in de2: + de2.Key); if (ht2.ContainsKey(de.Key)) { if (de2.Value != de.Value) { Results.Items.Add(This file has been changed + de.Value); } } }

Jitendra Tiwari · Answer

hello friends  try this code Hashtable ht1 = new Hashtable(); Hashtable ht2 = new Hashtable(); ht1.Add(1 AAA); ht1.Add(2 BBB); ht1.Add(3 CCC); ht2.Add(1 AAA); ht2.Add(2 BBB); ht2.Add(3 CCC); ht2.Add(4 DDD); ht2.Add(5 EEE); ht2.Add(6 FFF); string match = ; string unMatch = ; foreach (int n in ht2.Keys) { if (ht1.Contains(n)) { match += n +  ; } else { unMatch += n +  ; } } Response.Write(Matched : + match); Response.Write(Matched : + unMatch); if help u please mark answer thanks

vi M · Answer

Yes I'm using the Hashtable class..

Sam Hobbs · Answer

Are you using the Hashtable Class or something else for the hash table?