> with( StringTools ): # bind package exports at the top-level
> s := "dzrIemaWWIMidXYZwGiqkOOn":
> s[1..4]; # pick a prefix
                                 "dzrI"

> IsPrefix( s[ 1 .. 4 ], s ); # check it
                                  true

> s[ -4 .. -1 ]; # pick a suffix
                                 "kOOn"

> IsSuffix( s[ -4 .. -1 ], s ); # check it
                                  true

> p := Search( "XYZ", s ); # find a substring
                                p := 14

> s[ p .. p + 2 ]; # check
                                 "XYZ"

> SearchAll( [ "WWI", "XYZ" ], s ); # search for multiple patterns
                            [8, 1], [14, 2]

> to 3 do s := cat( s, s ) end: length( s ); # build a longer string by repeated doubling
                                  192

> p := SearchAll( "XYZ", s ); # find all occurrences
                p := 14, 38, 62, 86, 110, 134, 158, 182

> {seq}( s[ i .. i + 2 ], i = p ); # check them
                                {"XYZ"}