Syntax Error in Undefined Check for Corrected UTM Source

Elena M. · 2025-05-07 09:03:04.628104+00

what is wrong about this syntax? I want to check if the “corrected utm source” property is not defined: IF(UNDEFINED(`Corrected UTM Source`),TRUE,FALSE)

Syntax Error in Undefined Check for Corrected UTM Source | Mixpanel Community

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kapa.ai
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kapa.ai
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There are a few issues with your syntax for checking if the "Corrected UTM Source" property is not defined in Mixpanel: 1. The function name should be lowercase if instead of uppercase IF 2. The correct function to check if a property is defined is defined(), not UNDEFINED() 3. You should not use backticks () around property names in Mixpanel expressions 4. Property names should be referenced using the properties["Property Name"]syntaxLBKSThe correct syntax would be: LBKSLBKS```LBKSif(not defined(properties["Corrected UTM Source"]), true, false)LBKS```LBKSLBKSOr more simply: LBKSLBKS```LBKSnot defined(properties["Corrected UTM Source"])LBKS```LBKSLBKSThis is because thedefined()function already returns a boolean value, so wrapping it in an if statement that returns true/false is redundant.LBKSAccording to the Mixpanel documentation on segmentation expressions, thedefined()function "determines if a value exists. If a property is not defined on a parent event or profile, this will return false, otherwise this will return true." [Custom Properties](https://docs.mixpanel.com/docs/features/custom-properties#functions)LBKSThenotoperator can be used to negate the result of thedefined()` function, returning true when the property is not defined.
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