When using one of the functions in Figure 17–3, the elements E of a sequence S are filtered not on the basis of the presence or absence of an object O under a two argument predicate, as with the functions described in Satisfying a Two-Argument Test, but rather on the basis of a one argument predicate.
| assoc-if | member-if | rassoc-if |
| assoc-if-not | member-if-not | rassoc-if-not |
| count-if | nsubst-if | remove-if |
| count-if-not | nsubst-if-not | remove-if-not |
| delete-if | nsubstitute-if | subst-if |
| delete-if-not | nsubstitute-if-not | subst-if-not |
| find-if | position-if | substitute-if |
| find-if-not | position-if-not | substitute-if-not |
The element E_i might not be considered directly.
If a :key argument is provided,
it is a designator for a function of one argument
to be called with each E_i as an argument,
and yielding an object Z_i to be used for comparison.
(If there is no :key argument, Z_i is E_i.)
Functions defined in this specification and having a name that
ends in "-if" accept a first argument that is a designator for a
function of one argument, Z_i.
An E_i is said to satisfy the test
if this :test function
returns a generalized boolean representing true.
Functions defined in this specification and having a name that
ends in "-if-not" accept a first argument that is a designator for a
function of one argument, Z_i.
An E_i is said to satisfy the test
if this :test function
returns a generalized boolean representing false.
| Examples of Satisfying a One-Argument Test |