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21.4.7 String Comparison
The procedures in this section are similar to the character ordering
predicates (see Characters), but are defined on character sequences.
They all return #t
on success and #f
on failure. The
predicates ending in ci
ignore the character case when comparing
strings.
string=? s1 s2

Scheme Procedure 
Lexicographic equality predicate; return #t if the two
strings are the same length and contain the same characters in
the same positions, otherwise return #f .
The procedure stringci=? treats upper and lower case
letters as though they were the same character, but
string=? treats upper and lower case as distinct
characters.

string<? s1 s2

Scheme Procedure 
Lexicographic ordering predicate; return #t if s1
is lexicographically less than s2.

string<=? s1 s2

Scheme Procedure 
Lexicographic ordering predicate; return #t if s1
is lexicographically less than or equal to s2.

string>? s1 s2

Scheme Procedure 
Lexicographic ordering predicate; return #t if s1
is lexicographically greater than s2.

string>=? s1 s2

Scheme Procedure 
Lexicographic ordering predicate; return #t if s1
is lexicographically greater than or equal to s2.

stringci=? s1 s2

Scheme Procedure 
Caseinsensitive string equality predicate; return #t if
the two strings are the same length and their component
characters match (ignoring case) at each position; otherwise
return #f .

stringci<? s1 s2

Scheme Procedure 
Case insensitive lexicographic ordering predicate; return
#t if s1 is lexicographically less than s2
regardless of case.

stringci<=? s1 s2

Scheme Procedure 
Case insensitive lexicographic ordering predicate; return
#t if s1 is lexicographically less than or equal
to s2 regardless of case.

stringci>? s1 s2

Scheme Procedure 
Case insensitive lexicographic ordering predicate; return
#t if s1 is lexicographically greater than
s2 regardless of case.

stringci>=? s1 s2

Scheme Procedure 
Case insensitive lexicographic ordering predicate; return
#t if s1 is lexicographically greater than or
equal to s2 regardless of case.
