Type Functions
Type functions perform operations that check or convert expressions.
Type-Checking Functions
ISARRAY(expression)
Returns True if expression is an array, otherwise returns MISSING, NULL or false.
ISATOM(expression)
Returns True if expression is a Boolean, number, or string, otherwise returns MISSING, NULL or false.
ISBOOLEAN(expression)
Returns True if expression is a Boolean, otherwise returns MISSING, NULL or false.
ISNUMBER(expression)
Returns True if expression is a number, otherwise returns MISSING, NULL or false.
ISOBJECT(expression)
Returns True if expression is an object, otherwise returns MISSING, NULL or false.
ISSTRING(expression)
Returns True if expression is a string, otherwise returns MISSING, NULL or false.
TYPE(expression)
Returns one of the following strings, based on the value of expression:
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"missing"
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"null"
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"boolean"
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"number"
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"string"
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"array"
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"object"
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"binary"
Type-Conversion Functions
TOARRAY(expression)
Returns array as follows:
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MISSING is MISSING.
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NULL is NULL.
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Arrays are themselves.
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All other values are wrapped in an array.
TOATOM(expression)
Returns atomic value as follows:
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MISSING is MISSING.
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NULL is NULL.
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Arrays of length 1 are the result of TOATOM() on their single element.
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Objects of length 1 are the result of TOATOM() on their single value.
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Booleans, numbers, and strings are themselves.
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All other values are NULL.
TOBOOLEAN(expression)
Returns Boolean as follows:
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MISSING is MISSING.
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NULL is NULL.
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False is false.
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Numbers +0, -0, and NaN are false.
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Empty strings, arrays, and objects are false.
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All other values are true.
TONUMBER(expression)
Returns number as follows:
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MISSING is MISSING.
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NULL is NULL.
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False is 0.
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True is 1.
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Numbers are themselves.
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Strings that parse as numbers are those numbers.
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All other values are NULL.
TOOBJECT(expression)
Returns object as follows:
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MISSING is MISSING.
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NULL is NULL.
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Objects are themselves.
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All other values are the empty object.
TOSTRING(expression)
Returns string as follows:
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MISSING is MISSING.
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NULL is NULL.
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False is "false".
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True is "true".
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Numbers are their string representation.
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Strings are themselves.
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All other values are NULL.