I am new to Apex and cannot seem to find a solution to the error below on the last line of code. The error I get when compiling is "Method does not exist or incorrect signature: void get(Decimal) from the type List". Any help would be awesome. Thanks.

trigger LeadingCompetitor on Opportunity (before insert, before update) {

    for (Opportunity opp : Trigger.new) {
        List<Decimal> competitorPrices = new List<Decimal>();

        List<String> competitors = new List<String>();

        Decimal highestPrice;
        Integer highestPricePosition; 
        for (Integer i = 0; i < competitorPrices.size(); i++) {
            Decimal currentPrice = competitorPrices.get(i);
            if (highestPrice == null || currentPrice > highestPrice) {
                highestPrice = currentPrice;
                highestPricePosition = i;

        opp.Highest_Priced_Competitor__c = competitors.get(highestPricePosition);
        opp.Highest_Price__c = competitorPrices.get(highestPrice);

2 Answers 2


You're using the wrong index variable.

    opp.Highest_Priced_Competitor__c = competitors.get(highestPricePosition);
    opp.Highest_Price__c = competitorPrices.get(highestPrice);

The second line should also be using highestPricePosition, which is an Integer- or simply assigning highestPrice directly, since you do gather that value in your loop.

Arrays are not indexed by Decimal values, which is why the method get(Decimal) does not exist.


Array indices are Integer values, not Decimal values. You have to explicitly convert a Decimal to an Integer because it causes data loss, something you wouldn't want to accidentally do.

Decimal a = 3.14;
Integer b = a; // If this worked, would equal 3, not 3.14!

Aside from that, do not use the List.get method. It is slower (CPU-wise), more tedious to type, and causes confusion to readers of your code (as the Map class also has a get method).

By using the more common [] notation, you get better performance, easier to understand code, and more concise code.

opp.Highest_Priced_Competitor__c = competitors[highestPricePosition];
opp.Highest_Price__c = highestPrice;

Also, notice how we already know what the highest price is; just assign it directly instead of getting it from the list.

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