is.logical()
length()
For more details about the use of this function,
please read the article
vignette("chk-families")
.
Other logical_checkers:
chk_false()
,
chk_lgl()
,
chk_logical()
,
chk_true()
Other scalar_checkers:
chk_count()
,
chk_date()
,
chk_date_time()
,
chk_false()
,
chk_lgl()
,
chk_scalar()
,
chk_string()
,
chk_true()
,
chk_tz()