rindex(p1, p2 = v2)
public
Returns the index of the last occurrence
of the given substring or pattern (regexp) in
str. Returns nil if not found. If the second parameter is present,
it specifies the position in the string to end the search—characters
beyond this point will not be considered.
"hello".rindex('e')
"hello".rindex('l')
"hello".rindex('a')
"hello".rindex(?e)
"hello".rindex(/[aeiou]/, -2)
Show source
static VALUE
rb_str_rindex_m(int argc, VALUE *argv, VALUE str)
{
VALUE sub;
VALUE vpos;
rb_encoding *enc = STR_ENC_GET(str);
long pos, len = str_strlen(str, enc);
if (rb_scan_args(argc, argv, "11", &sub, &vpos) == 2) {
pos = NUM2LONG(vpos);
if (pos < 0) {
pos += len;
if (pos < 0) {
if (TYPE(sub) == T_REGEXP) {
rb_backref_set(Qnil);
}
return Qnil;
}
}
if (pos > len) pos = len;
}
else {
pos = len;
}
switch (TYPE(sub)) {
case T_REGEXP:
/* enc = rb_get_check(str, sub); */
pos = str_offset(RSTRING_PTR(str), RSTRING_END(str), pos,
STR_ENC_GET(str), single_byte_optimizable(str));
if (!RREGEXP(sub)->ptr || RREGEXP_SRC_LEN(sub)) {
pos = rb_reg_search(sub, str, pos, 1);
pos = rb_str_sublen(str, pos);
}
if (pos >= 0) return LONG2NUM(pos);
break;
default: {
VALUE tmp;
tmp = rb_check_string_type(sub);
if (NIL_P(tmp)) {
rb_raise(rb_eTypeError, "type mismatch: %s given",
rb_obj_classname(sub));
}
sub = tmp;
}
/* fall through */
case T_STRING:
pos = rb_str_rindex(str, sub, pos);
if (pos >= 0) return LONG2NUM(pos);
break;
}
return Qnil;
}