A set of unique keys linked to a set of values. Each unique key is associated with a value. Think of it as a two column table.
MyArray['CA'] = 'California'
MyArray['AR'] = 'Arizona'
Associative arrays are also known as a dictionary or a hash table in other languages.
Access VBA:
Collection
In addition to Add and Item, collections also offer Count and Remove . Notice that Add uses the format of Value, Key (which is backwards from many other languages).
Syntax Example: Dim States As New Collection States.Add "California", "CA" States.Add "Nevada", "NV" MsgBox (States.Item("CA"))
ASP Classic:
Scripting.Dictionary
Use the scriptiing dictionary object which is available on later versions of ASP Classic (all still commonly in use).
Note: Both Access VBA and VB Classic use a collection for this but collections are not supported in ASP Classic.
Syntax Example: Dim StateList set StateList = Server.CreateObject("Scripting.Dictionary") StateList.Add "CA", "California" StateList.Add "NV", "Nevada" Response.Write "I live in " & StateList.Item("CA")
C#:
Dictionary
Syntax Example: //using System.Collections.Generic; Dictionary <String, String> airports = new Dictionary <String, String>(); airports.Add("LAX", "Los Angeles"); airports.Add("SFO", "San Francisco"); airports.Add("SAN", "San Diego"); MessageBox.Show(airports["LAX"]);
C++:
map
Syntax Example: map<string, int> mymap; mymap.insert(AValuePair);
Corel Paradox:
DynArray
In ObjectPAL associative arrays are known as dynamic arrays.
Syntax Example: var myDynArray DynArray[] String endVar myDynArray["Last_Name"] = "Spitz" myDynArray["First_Name"] = "Randy" myDynArray.view()
Delphi:
TStringList Assoc Array
Object Pascal doesn't have a native associative array, but you can use a TStringList the same way. (Alternatively, search the Internet for TStringHash and THashedStringList classes for implementations of a true associative array).
Syntax Example:
var StateList : TStringList; begin StateList := TStringList.Create; StateList.CommaText := 'CA=California, FL=Florida'; ShowMessage('FL is ' + StateList.Values['FL']); end;
Java:
HashMap()
An associative array links a set of keys to a set of values. In Java, associative arrays are implemented as Maps.
This will print "Arizona."
Syntax Example:
import java.util.*; public class Maps { public static void main(String[] args) { Map states = new HashMap(); states.put("CA", "California"); states.put("FL", "Florida"); states.put("AZ", "Arizona"); System.out.println(states.get("AZ")); } }
JavaScript:
Array(), use [
Syntax Example:
var MyStateList= new Array() MyStateList["CA"]="California"; MyStateList["OR"]="Oregon"; Alert("OR is " + MyStateList["OR"])
Perl:
% Array Preface
Syntax Example: my %weekdays = ( 'Sun' => 'Sunday', 'Mon' => 'Monday', 'Tue' => 'Tuesday', 'Wed' => 'Wednesday', 'Thu' => 'Thursday', 'Fri' => 'Friday', 'Sat' => 'Saturday', ); my $day_of_the_week = $weekdays{'Mon'};
PHP:
Declare associative array with initial known values. You can also add to associative array. (You can just assign values without ever declaring it too!)
Syntax Example: $prices = array( 'Tires'=>100, 'Spark Plugs'=>4 ); $prices['Oil'] = 10; echo "Tires=" . $prices['Tires'] . "<br>"; echo "Oil=" . $prices['Oil'] . "<br>";
VB Classic:
Collection
In addition to Add and Item, collections also offer Count and Remove . Notice that Add uses the format of Value, Key (which is backwards from many other languages).
Syntax Example: Dim States As New Collection States.Add "California", "CA" States.Add "Nevada", "NV" MsgBox (States.Item("CA"))
VB.Net:
Dictionary
An associative array links a set of keys to a set of values. In Visual Basic, associative arrays are implemented as Dictionaries.
This code produces a message box saying "Nevada."
Syntax Example:
//Imports System.Collections.Generic � Dim States As New Dictionary(Of String, String) States.Add("CA", "California") States.Add("NV", "Nevada") MsgBox(States("NV"))