Expression Builder Scripting in BIRT 4.5

Istabrak

<p>Greeting to all,</p>
<p>I am using BIRT 4.5 bundled with Eclipse.</p>
<p>One of the data sets I am working on is a csv file with 500 or so columns.</p>
<p>Data fields in these columns are mostly numerical.</p>
<p>I have a requirement to add a number of computed columns.</p>
<p>The field values of these columns will be the sum of some of the fields of original 500 columns on the same row.</p>
<p>I tried using the Expression Builder but that takes a long time to do and error prone.</p>
<p>Is there a way to write a script or other APIs where these computed columns fields expressions can be defined? For example:</p>
<p>- ComputedCol-1 = Sum (col1 to col 20).</p>
<p>- ComputedCol-2 = Sum (col21, col27, col30).</p>
<p> </p>
<p>And so on.</p>
<p> </p>
<p>Thx and BR</p>

pricher

<p>Hi,</p>
<p> </p>
<p>Assuming that you read in your CSV file and you let BIRT name the columns automatically (e.g. COLUMN_1, COLUMN_2, etc) you can add Computed Columns in the Data Set and use one of the following scripts:</p>
<p> </p>
<p>1. For adding columns that are in a range (e.g. columns 1 to 5):</p>
<pre class="_prettyXprint _lang-js">
var tot = 0;
var startCol = 1;
var endCol = 5;
for (idx = startCol; idx <= endCol; idx++) {
tot += row["COLUMN_" + idx]
}
</pre>
<p>2. For adding discrete columns (e.g. Column 1, column 2, columns 5):</p>
<pre class="_prettyXprint _lang-js">
var tot = 0;
var cols = [1,2,5];
for (idx = 0; idx < cols.length; idx++) {
tot += row["COLUMN_" + cols[idx]]
}
</pre>
<p>I have attached a sample report and data file.</p>
<p> </p>
<p>Hope this helps,</p>
<p> </p>
<p>P.</p>