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Arcade When expression returning no results

Question asked by derek.phyn_WRC on Jul 15, 2019
Latest reply on Jul 17, 2019 by xander_bakker
  • Comment • 3

Hi All, I'm relatively new to Arcade but can't figure out this When function. I have a Right expression that returns the last three characters of a field $feature.info_headline when applied as a separate arcade expression. However when I apply the same expression as a variable in front of a When expression I get no errors when tested but also no results are returned? Can someone point me where I am going wrong with this expression? Is there a rule about variables I am missing?

 

var right3 = Right($feature.info_headline, 3);
var warning_level = When(right3=='Red', 'Red', right3=='nge', 'Orange', 'Watch');

 

I'm trying to get the expression to populate a new Color Style such that if the last three characters in the field $feature.info_headline are 'Red' the value returned is 'Red', or if he last three characters are 'nge' the value returned is 'Orange', else return 'Watch'.


I know there might be some options using nested IIf functions but thought the When function would be simple enough to do what I am trying.


Cheers

Derek

xander_bakker
xander_bakker Jul 17, 2019 5:18 AM
Correct Answer

Hi Derek Phyn ,

 

That is correct you should always return the result of the expression. 

 

For readability especially when you have a lot of values to check you could spread the "when parts" over multiple lines like this:

var right3 = Right($feature.info_headline, 3);
return When(right3=='Red', 'Warning - Red', 
            right3=='nge', 'Warning - Orange', 
            'Watch');

 

I also often use if - else if - else statements:

var right3 = Right($feature.info_headline, 3);
if (right3 == 'Red') {
    return 'Warning - Red';
} else if (right3 == 'nge') {
    return 'Warning - Orange';
} else {
    return 'Watch';
}

 

You can also use a dictionary with the options:

var right3 = Right($feature.info_headline, 3);
var dct = {'Red': 'Warning - Red',
           'nge': 'Warning - Orange'};
if (HasKey(dct, right3)) {
    return dct[right3];
} else {
    return 'Watch';
}
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    Last modified on Jul 15, 2019 6:39 PM