The function ISEMPTY returns TRUE if the given object, string, or list is empty.
This function takes an object, string, or list as input. It outputs a boolean indicating whether the given object, string, or list is empty: TRUE means that it is empty, FALSE means that it is not. It can also accept NULL as input, in which case it will return TRUE.
Declaration
ISEMPTY(var) -> bool
Parameters
- var (type: object | string | array | NULL)
- Any object, string, or list. It will also accept a lack of value, or NULL, as valid input.
Return Values
- bool (type: boolean)
- A boolean indicating if var is empty. It will output TRUE if it is empty and FALSE otherwise.
Examples
The first example checks to see if an empty list is empty; that is, if the empty list does not contain any items. It does not:
ISEMPTY([]) -> TRUE
The following example checks to see if a blank string is empty; that is, if the blank string does not contain any characters. It does not:
ISEMPTY("") -> TRUE
The following example checks to see if a list containing a single blank string is empty. This list does not count as empty – it contains an item, even that item is only a single blank string:
ISEMPTY([""]) -> FALSE
The following example checks to see if an object containing no name-value pairs is empty. The complete lack of name-value pairs makes this object empty by definition:
ISEMPTY({}) -> TRUE
The following example checks to see if an object containing a single name-value pair – in which the name and the value are both blank strings – is empty. While the name and value are both blank strings, their existence means that the object contains name-value pair, and thus the object doesn't count as empty:
ISEMPTY({"": ""}) -> FALSE
The last example checks if NULL – the lack of any value – is empty. For the purposes of the ISEMPTY function, lack of any value counts as empty:
ISEMPTY(NULL) -> TRUE
Discussion
The ISEMPTY function can be considered the opposite of the ISNOTEMPTY function: they check for the same thing, but ISNOTEMPTY returns FALSE when ISEMPTY would return TRUE and visa versa.
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