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:) :) :) :) :) How to select random element from Set<String>
Set<String> setUserID = new Set<String>{'1','55','80','12', '6','22','87'};
Now I want to select random element from it. Below random method is not yet exist. So how can I select random element from this set. Any other idea?
System.debug('Random Set Element = ' +setUserID.random());
You really have two options.
The first option is to generate a random index, convert the set to a list, and fetch the list element using the bracket notation.
Set<String> setArray = new Set<String> {'a', 'b', 'c'};// Convert the Set to a list
List<String> lstArray = new List<String>();
lstArray.addAll(setArray);
//Generate a random list index
Double randomNumber = Math.random();
Integer arrayLength = lstArray.size());
Integer randomIndex = (randomNumber *(arrayLength-1)).intValue();
//Output the element at the list index generated above
System.debug('Random element: '+lstArray[randomIndex]);
The second option is to generate the random index, then iterate through the Set until you get to the appropriate element.
// Generate the set Set<String> setArray = new Set<String> {'a', 'b', 'c'}; // Create a random index Double randomNumber = Math.random(); Integer arraySize = setArray.size(); Integer randomIndex = (randomNumber *(arraySize-1)).intValue(); // Loop through the Set until you get to the element. for (String str : setArray) { if (randomIndex == 0) { System.debug('Random element: '+str); break; } randomIndex--; }All Answers
Ketan1248,
You can use our crypto or math classes to grab random numbers. Use that random number as an index for retrieval. Check here for more: http://www.salesforce.com/us/developer/docs/apexcode/Content/apex_classes_restful_crypto.htm and here: http://www.salesforce.com/us/developer/docs/apexcode/Content/apex_methods_system_math.htm.
Set<String> setUserID = new Set<String>{'1','55','80','12', '6','22','87'}; System.debug(LoggingLevel.Error,(new List<String>(setUserId))[Math.mod(Math.abs(Crypto.getRandomLong().intValue()),setUserId.size())]);Convert to a list, then pull out a random element.
You really have two options.
The first option is to generate a random index, convert the set to a list, and fetch the list element using the bracket notation.
Set<String> setArray = new Set<String> {'a', 'b', 'c'};// Convert the Set to a list
List<String> lstArray = new List<String>();
lstArray.addAll(setArray);
//Generate a random list index
Double randomNumber = Math.random();
Integer arrayLength = lstArray.size());
Integer randomIndex = (randomNumber *(arrayLength-1)).intValue();
//Output the element at the list index generated above
System.debug('Random element: '+lstArray[randomIndex]);
The second option is to generate the random index, then iterate through the Set until you get to the appropriate element.
// Generate the set Set<String> setArray = new Set<String> {'a', 'b', 'c'}; // Create a random index Double randomNumber = Math.random(); Integer arraySize = setArray.size(); Integer randomIndex = (randomNumber *(arraySize-1)).intValue(); // Loop through the Set until you get to the element. for (String str : setArray) { if (randomIndex == 0) { System.debug('Random element: '+str); break; } randomIndex--; }Id randomid = mylist[math.random() * (mylist.size()-1)]