method

rindex

v1_8_7_72 - Show latest stable - Class: String

rindex(...)

public

Returns the index of the last occurrence of the given substring, character (fixnum), 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')             #=> 1
   "hello".rindex('l')             #=> 3
   "hello".rindex('a')             #=> nil
   "hello".rindex(101)             #=> 1
   "hello".rindex(/[aeiou]/, -2)   #=> 1

/*
 *  call-seq:
 *     str.rindex(substring [, fixnum])   => fixnum or nil
 *     str.rindex(fixnum [, fixnum])   => fixnum or nil
 *     str.rindex(regexp [, fixnum])   => fixnum or nil
 *  
 *  Returns the index of the last occurrence of the given <i>substring</i>,
 *  character (<i>fixnum</i>), or pattern (<i>regexp</i>) in <i>str</i>. Returns
 *  <code>nil</code> 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')             #=> 1
 *     "hello".rindex('l')             #=> 3
 *     "hello".rindex('a')             #=> nil
 *     "hello".rindex(101)             #=> 1
 *     "hello".rindex(/[aeiou]/, -2)   #=> 1
 */

static VALUE
rb_str_rindex_m(argc, argv, str)
    int argc;
    VALUE *argv;
    VALUE str;
{
    VALUE sub;
    VALUE position;
    long pos;

    if (rb_scan_args(argc, argv, "11", &sub, &position) == 2) {
        pos = NUM2LONG(position);
        if (pos < 0) {
            pos += RSTRING(str)->len;
            if (pos < 0) {
                if (TYPE(sub) == T_REGEXP) {
                    rb_backref_set(Qnil);
                }
                return Qnil;
            }
        }
        if (pos > RSTRING(str)->len) pos = RSTRING(str)->len;
    }
    else {
        pos = RSTRING(str)->len;
    }

    switch (TYPE(sub)) {
      case T_REGEXP:
        if (RREGEXP(sub)->len) {
            pos = rb_reg_adjust_startpos(sub, str, pos, 1);
            pos = rb_reg_search(sub, str, pos, 1);
        }
        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;

      case T_FIXNUM: {
        int c = FIX2INT(sub);
        unsigned char *p = (unsigned char*)RSTRING(str)->ptr + pos;
        unsigned char *pbeg = (unsigned char*)RSTRING(str)->ptr;

        if (pos == RSTRING(str)->len) {
            if (pos == 0) return Qnil;
            --p;
        }
        while (pbeg <= p) {
            if (*p == c) return LONG2NUM((char*)p - RSTRING(str)->ptr);
            p--;
        }
        return Qnil;
      }
    }
    return Qnil;
}

rindex

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