https://community.appian.com/discussions/f/user-interface/18374/choose-functionExpression evaluation error in rule &#39;regat_ca_getconstantbycategory&#39; (called by rule &#39;regat_ca_constantmanagement&#39;) at function &#39;choose&#39;: Choose index cannot be null.en-USTelligent Community 12https://community.appian.com/thread/72382?ContentTypeID=1Thu, 27 Feb 2020 04:51:02 GMTd3a83456-d57b-489c-a84c-4e8267bb592a:ec3de4fe-4452-4c4d-adc2-410949928495Salma Khan<p>thanks it worked</p><div style="clear:both;"></div>https://community.appian.com/thread/72362?ContentTypeID=1Wed, 26 Feb 2020 13:24:34 GMTd3a83456-d57b-489c-a84c-4e8267bb592a:573a0e1d-b3aa-4dd5-b941-918bcbfc10e2davel001150<p>You&#39;re passing an integer into the rule, or creating a local variable that is an integer, and using it to evaluate the choose function.&nbsp; At some point, that value was null and the choose function crashed.</p> <p>Two possibilities:</p> <p>1&nbsp; Your integer, whatever it is, should never be null by that point, and you have a bug you need to investigate to find out why that integer is null.</p> <p>2&nbsp; Your integer could be null sometimes as a perfectly valid value.</p> <p>In either case, you will probably want to&nbsp;wrap your whole choose function inside an if().&nbsp; if(isnull(), null response, choose() )</p><div style="clear:both;"></div>