How to convert hash table to string?

In C#, the hashtable collection is a non-generic collection of elements. Each element of the hashtable is represented as a key-value pair. The keys of the hashtable are non-null and unique. Values ​​can be repeated and/or empty.

Hashtable class for C# Systems. The collection interface is a representation of a hashtable collection. This class provides various constructors, methods, and properties to manipulate hashtable collections.

We can also convert the hash table to other collections, such as arrays, ArrayList, etc., and also to string representation.

In this article, let us discuss how to convert a collection of hash tables into strings.

How to convert a hash table entry to a string?

Please note that to convert a hash table item to a string, the hash table class does not provide a direct method like Java does. There are also no built-in properties to do the conversion. Therefore, we need to design our own method to perform the conversion.

Hash table elements are converted to string representations.

To do this, we have to iterate through the hash table collection and copy the key and value of each item into a string. We can use delimiters to separate each key-value item in the string.

To actually program in C#, we use an IDictionaryEnumerator to iterate over each item in the hash table. The enumerator holds each item (key and value) of the hash table. We can then use a loop to copy each key and value into a string as shown below.

IDictionaryEnumerator enumerator = phonetics.GetEnumerator();
while (enumerator.MoveNext()) {
   text += enumerator.Key + ", ";
   text += enumerator.Value + "";
}

As we can see in the code above, after copying each key-value pair to a string, we insert a delimiter "

" so that each item is separated.

Example

The following is the complete C# program to convert a hash table item to a string.

using System;
using System.Collections;
class myHashTable {
   public static void Main() {
      // Create a Hashtable named phonetics
      Hashtable phonetics = new Hashtable();
      
      // Add key/value pairs in phonetics
      phonetics.Add("A", "Apple");
      phonetics.Add("B", "Banana");
      phonetics.Add("C", "Cat");
      phonetics.Add("D", "Dog");
      phonetics.Add("E", "Elephant");
      phonetics.Add("F", "Fish");
      
      //print hahshtable collection
      Console.WriteLine("Hashtable items:");
      foreach(DictionaryEntry entry in phonetics){
         Console.WriteLine("{0} and {1} ", entry.Key, entry.Value);
      }
      string text = "";
      IDictionaryEnumerator enumerator = phonetics.GetEnumerator();
      while (enumerator.MoveNext()) {
         text += enumerator.Key + ", ";
         text += enumerator.Value + "";
      }
      Console.WriteLine("String value: {0}", text);
   }
}

In this program, we have a hash table of phonetic symbols from A to F. We declare a string variable 'text'. Then we declare an IDictionaryEnumerator to iterate over the hash table. Then using this enumerator, we use a 'while' loop to copy the contents of the hash table collection into a string.

Output

The program generates the following output.

Hashtable items:
B and Banana 
C and Cat A and Apple 
F and Fish 
D and Dog 
E and Elephant 
String value: B, Banana
C, Cat
A, Apple
F, FishD, Dog
E, Elephant

Here, we first display the contents of the hash table collection. Next, we display the string. We can see that the string value consists of all elements of the hash table separated by ‘

’ (newline character).

Example

Let's implement another program to convert a hash table into a string. The complete C# program is shown below.

using System;
using System.Collections;
class myHashTable {
   public static void Main() {
      
      // Create a Hashtable named numberNames
      Hashtable numberNames = new Hashtable();
      
      // Add key/value pairs in numberNames
      numberNames.Add("10", "Ten");
      numberNames.Add("20", "Twenty");
      numberNames.Add("30", "Thirty");
      numberNames.Add("40", "Forty");
      numberNames.Add("50", "Fifty");
      numberNames.Add("60", "Sixty");
      
      //print hahshtable collection
      Console.WriteLine("Hashtable items:");
      foreach(DictionaryEntry entry in numberNames){
         Console.WriteLine("{0} => {1} ", entry.Key, entry.Value);
      }
      string text = "";
      IDictionaryEnumerator enumerator = numberNames.GetEnumerator();
      while (enumerator.MoveNext()) {
         text += enumerator.Key + " and ";
         text += enumerator.Value + "";
      }
      Console.WriteLine("String value: {0}", text);
   }
}

This program is similar to the previous one, with some minor changes in the way the hash table and string values ​​are displayed.

Here, we have a hash table with numbers as keys and their corresponding number names as values. We then use an IDictionaryEnumerator to declare an object that iterates over the hash table and copies each item (key and value) of the hash table into a string. Each hash table entry is separated by the delimiter '

'.

Output

The program generates the following output.

Hashtable items:
10 => Ten 
60 => Sixty 
40 => Forty 
50 => Fifty 
20 => Twenty 
30 => Thirty 
String value: 10 and Ten
60 and Sixty
40 and Forty
50 and Fifty
20 and Twenty
30 and Thirty

From the above output we can see that the hash table collection item has been successfully copied to the string variable.

So, in this article, we discussed converting a collection of hash tables into strings. Although there is no direct way to perform this conversion, we can easily convert a collection of hash tables to strings using the following command: IDictionaryEnumerator. It holds the items (keys and values) of the hash table, which we can easily access and copy into a string using a loop.

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