N_TAGS Function

Returns the number of structure tags contained in any expression.

result = N_TAGS(expr)

expr The expression for which the number of structure tags will be returned.

result The number of structure tags contained in any expression.

None.

Expressions which are not of structure type are considered to have zero tags. N_TAGS does not search for tags recursively, so if expr is a structure containing nested structures, only the number of tags in the outermost structure are counted.

In this example, a structure with three fields is created. Function N_TAGS is applied to the structure and to each field of the structure. The first two fields of the structure are not of type structure. The third field of the structure is of type structure, with two fields.

b = {example, t1: [1, 2, 3], t2: 7.0, $
    t3: {field3, t3_t1: 99L, t3_t2: [2, 4, 6]}}
INFO, b, /Structure
** Structure EXAMPLE, 3 tags, 32 length:

T1 INT	Array(3)
T2 FLOAT	7.00000
T3 STRUCT	- FIELD3 Array(1)

; Create the structure.

PRINT, N_TAGS(b)

; Display the number of tags in b.

PRINT, N_TAGS(b.t1)

; Display the number of tags in each field of b.

PRINT, N_TAGS(b.t2)

PRINT, N_TAGS(b.t3)

N_ELEMENTS, N_PARAMS, SIZE, STRUCTREF, TAG_NAMES