Skipping element in a for loop and reassigning it

I'm filling parameters in JasperSoft. In my report I have the Parameters: Parameter_1, Parameter_2, Parameter_3

int a; 
for (a = 0; a < headers.length; a++) {
        parameters.put("Parameter_" + a, headers[a]);
    }

I was populating the Parameters in this fashion and it works. Now I want to add a new Parameter, Parameter_GroupBy which is determined by its index (let's say I want Parameter_2 to be the Parameter_GroupBy) so I did this:

int a; 
for (a = 0; a < headers.length; a++) {
        if (a == groupBy) {
            parameters.put("Parameter_GroupBy", headers[groupBy]);
            continue; 
        }
        parameters.put("Parameter_" + a, headers[a]);
    }

The problem with this code (assuming groupBy value is 2) is that Parameter_2 is blank but I want it to have the content of what Parameter_3

For example 

Parameter_1= name 
Parameter_2= date 
Parameter_3= street

What I get with the second code bit

Parameter_1 = name 
Parameter_2= 
Parameter_GroupBy= date 
Parameter_3= street

I want to group by date (Parameter_2) so I want 

Parameter_1 = name 
Parameter_2= street 
Parameter_GroupBy= date 
Parameter_3=

How can this be achieved? Using JDK 1.6 and Windows.

Jon Skeet
people
quotationmark

It seems to me that you just need to keep a separate index for the "next parameter to put":

int parameterIndex = 1;
// Note: more idiomatic to declare the iteration variable
// inside the loop
for (int headerIndex = 0; headerIndex < headers.length; headerIndex++) {
    String header = headers[headerIndex];
    if (headerIndex == groupBy) {
        parameters.put("Parameter_GroupBy", header);
    } else {
        parameters.put("Parameter_" + parameterIndex, header);
        parameterIndex++;
    }
}

people

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