string1—a string designator.
string2—a string designator.
start1, end1—bounding index designators of string1.
The defaults for start and end are 0
and nil
, respectively.
start2, end2—bounding index designators of string2.
The defaults for start and end are 0
and nil
, respectively.
generalized-boolean—a generalized boolean.
mismatch-index—a bounding index of string1, or nil
.
These functions perform lexicographic comparisons on string1 and string2.
string=
and string-equal
are called equality functions;
the others are called inequality functions.
The comparison operations these functions perform are restricted
to the subsequence of string1 bounded by start1 and end1
and to the subsequence of string2 bounded by start2 and end2.
A string a is equal to a string b if it contains the same number
of characters, and the corresponding characters are the same
under char=
or char-equal
, as appropriate.
A string a is less than a string b if in the first position in
which they differ the character of a is less than the corresponding
character of b according to char<
or char-lessp
as appropriate, or if string a is a proper prefix of string b
(of shorter length and matching in all the characters of a).
The equality functions return a generalized boolean that is true if the strings are equal, or false otherwise.
The inequality functions return a mismatch-index that is true if the strings are not equal, or false otherwise. When the mismatch-index is true, it is an integer representing the first character position at which the two substrings differ, as an offset from the beginning of string1.
The comparison has one of the following results:
string=
string=
is true if the supplied substrings are of
the same length and contain the same characters in corresponding
positions; otherwise it is false.
string/=
string/=
is true if the supplied substrings are
different; otherwise it is false.
string-equal
string-equal
is just like string=
except that differences in case are ignored;
two characters are considered to be the same if char-equal
is true of them.
string<
string<
is true if substring1 is less than substring2;
otherwise it is false.
string>
string>
is true if substring1 is greater than substring2;
otherwise it is false.
string-lessp
, string-greaterp
string-lessp
and string-greaterp
are exactly like string<
and string>
, respectively,
except that distinctions between uppercase and lowercase letters are ignored.
It is as if char-lessp
were used instead of char<
for comparing characters.
string<=
string<=
is true if substring1 is less than or equal to substring2;
otherwise it is false.
string>=
string>=
is true if substring1 is greater than or equal to substring2;
otherwise it is false.
string-not-greaterp
, string-not-lessp
string-not-greaterp
and string-not-lessp
are exactly like string<=
and string>=
, respectively,
except that distinctions between uppercase and lowercase letters are ignored.
It is as if char-lessp
were used instead of char<
for comparing characters.
(string= "foo" "foo") → true (string= "foo" "Foo") → false (string= "foo" "bar") → false (string= "together" "frog" :start1 1 :end1 3 :start2 2) → true (string-equal "foo" "Foo") → true (string= "abcd" "01234abcd9012" :start2 5 :end2 9) → true (string< "aaaa" "aaab") → 3 (string>= "aaaaa" "aaaa") → 4 (string-not-greaterp "Abcde" "abcdE") → 5 (string-lessp "012AAAA789" "01aaab6" :start1 3 :end1 7 :start2 2 :end2 6) → 6 (string-not-equal "AAAA" "aaaA") → false
equal
calls string=
if applied to two strings.