TheSwamp

Code Red => .NET => Topic started by: TR on March 10, 2007, 02:04:25 PM

Title: Dictionaries in C#
Post by: TR on March 10, 2007, 02:04:25 PM

In boo I can create a dictionary to map objects to keywords. For example I can create a dictionary like the one below to groups lists of employees.

Code: [Select]

employees = {'engineers':['dave', 'charlie', 'michael', 'doug'], 'drafters':['gary', 'fredrico', 'jim', 'rich'], 'salesmen':['jim', 'eric', 'george', 'kerry']}


for user in employee['drafters']:
    print user

Returns:
gary
fredrico
jim
rich

For brevity sake I mapped them to lists of strings, but I could have used class instances or whatever. Is there an easy way to do something like this in C#?

Title: Re: Dictionaries in C#
Post by: TonyT on March 10, 2007, 02:27:43 PM

Here's one way:

Code: [Select]

// .NET 1.x


#using System.Collections;


public class MyClass
{
   public void Test()
   {
     Hashtable employees = new Hashtable();
    
     ArrayList drafters = new ArrayList(new string[] {"Dave", "Charlie", "Ed"});
     ArrayList engineers = new ArrayList(new string[] {"John", "Paul", "George", "Ringo"});
     ArrayList clerks = new ArrayList(new string[] {"Jane", "Sue"});
    
     employees["drafters"] = drafters;
     employees["engineers"] = engineers;
     employees["clerks"] = clerks;
    
     foreach( string name in employees["engineers"] )
       Console.WriteLine(name);
   }
}

// .NET 2.0

#using System.Collections.Generic;

public class MyClass
{
   public void Test()
   {
     Dictionary<string, List<string>> employees = new Dictionary<string, List<string>>();
    
     List<string> drafters = new List<string>(new string[] {"Dave", "Charlie", "Ed"});
     List<string> engineers = new List<string>(new string[] {"John", "Paul", "George", "Ringo"});
     List<string> clerks = new List<string>(new string[] {"Jane", "Sue"});
    
     employees["drafters"] = drafters;
     employees["engineers"] = engineers;
     employees["clerks"] = clerks;

     // dump one Dictionary entry's contents:    
    
     foreach( string name in employees["engineers"] )
       Console.WriteLine(name);
      
     // dump all Dictionary entries:
    
     foreach( KeyValuePair<string, List<string>> category in employees )
     {
        Console.WriteLine("Category {0}", category.Key);
        foreach( string name in category.Value )
           Console.WriteLine(name);
     }
   }

}


You could also use a StringDictionary as well, in
either version.

Quote from: Tim Riley on March 10, 2007, 02:04:25 PM

In boo I can create a dictionary to map objects to keywords. For example I can create a dictionary like the one below to groups lists of employees.

Code: [Select]

employees = {'engineers':['dave', 'charlie', 'michael', 'doug'], 'drafters':['gary', 'fredrico', 'jim', 'rich'], 'salesmen':['jim', 'eric', 'george', 'kerry']}


for user in employee['drafters']:
    print user

Returns:
gary
fredrico
jim
rich

For brevity sake I mapped them to lists of strings, but I could have used class instances or whatever. Is there an easy way to do something like this in C#?