StructKeyExists()

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Determines whether a specific key is present in a structure.

In CFML, by default, this will return false for any keys with a null value, however, if Full Null Support is enabled, it will return true.

Null Handling in CFML

See Also: Elvis and Safe Navigation Operators

For many common use cases, consider using these more concise alternatives:

  • Elvis operator (?:) - Returns a default value if the left side is null or undefined:

    // Instead of:
if ( structKeyExists( args, "name" ) ) {
    result = args.name;
} else {
    result = "default";
}
// Use:
result = args.name ?: "default";

  • Safe navigation operator (?.) - Safely traverse nested properties, combine with elvis for a default value:

    // Instead of:
if ( structKeyExists( user, "address" ) && structKeyExists( user.address, "city" ) ) {
    city = user.address.city;
} else {
    city = "Unknown";
}
// Use:
city = user?.address?.city ?: "Unknown";

    Operators

StructKeyExists( struct=struct, key=string );

Returns: Boolean

Argument Description
struct
struct, required 		edit

Name of structure to test

Alias: structure, object
key
string, required 		edit

Key to test

Usage Notes

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Using this function to check if a session variable exists, will create a session, if it doesn't already exist.

With Lucee 6.2, we have introduced SessionExists() which can be safely used to check if a session has been created

Examples

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Non-Member Function

animals = {
	cow: "moo",
	pig: "oink",
	cat: "meow",
	bird: "chirp"
};

// Check to see if key exists in struct
if (
	StructKeyExists(animals, "snail")
) {
	echo("There is a snail in 'animals'");
} else {
	echo("No snail exists in 'animals'");
}

See also