Class Range
In: range.c
Parent: Object

A Range represents an interval—a set of values with a start and an end. Ranges may be constructed using the s..e and se literals, or with Range::new. Ranges constructed using .. run from the start to the end inclusively. Those created using exclude the end value. When used as an iterator, ranges return each value in the sequence.

   (-1..-5).to_a      #=> []
   (-5..-1).to_a      #=> [-5, -4, -3, -2, -1]
   ('a'..'e').to_a    #=> ["a", "b", "c", "d", "e"]
   ('a'...'e').to_a   #=> ["a", "b", "c", "d"]

Ranges can be constructed using objects of any type, as long as the objects can be compared using their <=> operator and they support the succ method to return the next object in sequence.

   class Xs                # represent a string of 'x's
     include Comparable
     attr :length
     def initialize(n)
       @length = n
     end
     def succ
       Xs.new(@length + 1)
     end
     def <=>(other)
       @length <=> other.length
     end
     def to_s
       sprintf "%2d #{inspect}", @length
     end
     def inspect
       'x' * @length
     end
   end

   r = Xs.new(3)..Xs.new(6)   #=> xxx..xxxxxx
   r.to_a                     #=> [xxx, xxxx, xxxxx, xxxxxx]
   r.member?(Xs.new(5))       #=> true

In the previous code example, class Xs includes the Comparable module. This is because Enumerable#member? checks for equality using ==. Including Comparable ensures that the == method is defined in terms of the <=> method implemented in Xs.

Methods

==   ===   begin   each   end   eql?   exclude_end?   first   hash   include?   inspect   last   member?   new   step   to_s  

Included Modules

Enumerable

Public Class methods

Constructs a range using the given start and end. If the third parameter is omitted or is false, the range will include the end object; otherwise, it will be excluded.

[Source]

/*
 *  call-seq:
 *     Range.new(start, end, exclusive=false)    => range
 *  
 *  Constructs a range using the given <i>start</i> and <i>end</i>. If the third
 *  parameter is omitted or is <code>false</code>, the <i>range</i> will include
 *  the end object; otherwise, it will be excluded.
 */

static VALUE
range_initialize(argc, argv, range)
    int argc;
    VALUE *argv;
    VALUE range;
{
    VALUE beg, end, flags;
    
    rb_scan_args(argc, argv, "21", &beg, &end, &flags);
    /* Ranges are immutable, so that they should be initialized only once. */
    if (rb_ivar_defined(range, id_beg)) {
        rb_name_error(rb_intern("initialize"), "`initialize' called twice");
    }
    range_init(range, beg, end, RTEST(flags));
    return Qnil;
}

Public Instance methods

Returns true only if obj is a Range, has equivalent beginning and end items (by comparing them with ==), and has the same exclude_end? setting as <i>rng</t>.

  (0..2) == (0..2)            #=> true
  (0..2) == Range.new(0,2)    #=> true
  (0..2) == (0...2)           #=> false

[Source]

/*
 *  call-seq:
 *     rng == obj    => true or false
 *  
 *  Returns <code>true</code> only if <i>obj</i> is a Range, has equivalent
 *  beginning and end items (by comparing them with <code>==</code>), and has
 *  the same #exclude_end? setting as <i>rng</t>.
 *     
 *    (0..2) == (0..2)            #=> true
 *    (0..2) == Range.new(0,2)    #=> true
 *    (0..2) == (0...2)           #=> false
 *     
 */

static VALUE
range_eq(range, obj)
    VALUE range, obj;
{
    if (range == obj) return Qtrue;
    if (!rb_obj_is_instance_of(obj, rb_obj_class(range)))
        return Qfalse;

    if (!rb_equal(rb_ivar_get(range, id_beg), rb_ivar_get(obj, id_beg)))
        return Qfalse;
    if (!rb_equal(rb_ivar_get(range, id_end), rb_ivar_get(obj, id_end)))
        return Qfalse;

    if (EXCL(range) != EXCL(obj)) return Qfalse;

    return Qtrue;
}

Returns true if obj is an element of rng, false otherwise. Conveniently, === is the comparison operator used by case statements.

   case 79
   when 1..50   then   print "low\n"
   when 51..75  then   print "medium\n"
   when 76..100 then   print "high\n"
   end

produces:

   high

[Source]

/*
 *  call-seq:
 *     rng === obj       =>  true or false
 *     rng.member?(val)  =>  true or false
 *     rng.include?(val) =>  true or false
 *  
 *  Returns <code>true</code> if <i>obj</i> is an element of
 *  <i>rng</i>, <code>false</code> otherwise. Conveniently,
 *  <code>===</code> is the comparison operator used by
 *  <code>case</code> statements.
 *     
 *     case 79
 *     when 1..50   then   print "low\n"
 *     when 51..75  then   print "medium\n"
 *     when 76..100 then   print "high\n"
 *     end
 *     
 *  <em>produces:</em>
 *     
 *     high
 */

static VALUE
range_include(range, val)
    VALUE range, val;
{
    VALUE beg, end;

    beg = rb_ivar_get(range, id_beg);
    end = rb_ivar_get(range, id_end);
    if (r_le(beg, val)) {
        if (EXCL(range)) {
            if (r_lt(val, end)) return Qtrue;
        }
        else {
            if (r_le(val, end)) return Qtrue;
        }
    }
    return Qfalse;
}

Returns the first object in rng.

[Source]

/*
 *  call-seq:
 *     rng.first    => obj
 *     rng.begin    => obj
 *  
 *  Returns the first object in <i>rng</i>.
 */

static VALUE
range_first(range)
    VALUE range;
{
    return rb_ivar_get(range, id_beg);
}

Iterates over the elements rng, passing each in turn to the block. You can only iterate if the start object of the range supports the succ method (which means that you can‘t iterate over ranges of Float objects).

   (10..15).each do |n|
      print n, ' '
   end

produces:

   10 11 12 13 14 15

[Source]

/*
 *  call-seq:
 *     rng.each {| i | block } => rng
 *  
 *  Iterates over the elements <i>rng</i>, passing each in turn to the
 *  block. You can only iterate if the start object of the range
 *  supports the +succ+ method (which means that you can't iterate over
 *  ranges of +Float+ objects).
 *     
 *     (10..15).each do |n|
 *        print n, ' '
 *     end
 *     
 *  <em>produces:</em>
 *     
 *     10 11 12 13 14 15
 */

static VALUE
range_each(range)
    VALUE range;
{
    VALUE beg, end;

    RETURN_ENUMERATOR(range, 0, 0);

    beg = rb_ivar_get(range, id_beg);
    end = rb_ivar_get(range, id_end);

    if (!rb_respond_to(beg, id_succ)) {
        rb_raise(rb_eTypeError, "can't iterate from %s",
                 rb_obj_classname(beg));
    }
    if (FIXNUM_P(beg) && FIXNUM_P(end)) { /* fixnums are special */
        long lim = FIX2LONG(end);
        long i;

        if (!EXCL(range)) lim += 1;
        for (i=FIX2LONG(beg); i<lim; i++) {
            rb_yield(LONG2NUM(i));
        }
    }
    else if (TYPE(beg) == T_STRING) {
        VALUE args[5], iter[2];

        args[0] = beg; args[1] = end; args[2] = range;
        iter[0] = INT2FIX(1); iter[1] = INT2FIX(1);
        rb_iterate((VALUE(*)_((VALUE)))str_step, (VALUE)args, step_i,
                   (VALUE)iter);
    }
    else {
        range_each_func(range, each_i, beg, end, NULL);
    }
    return range;
}

Returns the object that defines the end of rng.

   (1..10).end    #=> 10
   (1...10).end   #=> 10

[Source]

/*
 *  call-seq:
 *     rng.end    => obj
 *     rng.last   => obj
 *  
 *  Returns the object that defines the end of <i>rng</i>.
 *     
 *     (1..10).end    #=> 10
 *     (1...10).end   #=> 10
 */


static VALUE
range_last(range)
    VALUE range;
{
    return rb_ivar_get(range, id_end);
}

Returns true only if obj is a Range, has equivalent beginning and end items (by comparing them with eql?), and has the same exclude_end? setting as rng.

  (0..2) == (0..2)            #=> true
  (0..2) == Range.new(0,2)    #=> true
  (0..2) == (0...2)           #=> false

[Source]

/*
 *  call-seq:
 *     rng.eql?(obj)    => true or false
 *  
 *  Returns <code>true</code> only if <i>obj</i> is a Range, has equivalent
 *  beginning and end items (by comparing them with #eql?), and has the same
 *  #exclude_end? setting as <i>rng</i>.
 *     
 *    (0..2) == (0..2)            #=> true
 *    (0..2) == Range.new(0,2)    #=> true
 *    (0..2) == (0...2)           #=> false
 *     
 */

static VALUE
range_eql(range, obj)
    VALUE range, obj;
{
    if (range == obj) return Qtrue;
    if (!rb_obj_is_instance_of(obj, rb_obj_class(range)))
        return Qfalse;

    if (!rb_eql(rb_ivar_get(range, id_beg), rb_ivar_get(obj, id_beg)))
        return Qfalse;
    if (!rb_eql(rb_ivar_get(range, id_end), rb_ivar_get(obj, id_end)))
        return Qfalse;

    if (EXCL(range) != EXCL(obj)) return Qfalse;

    return Qtrue;
}

Returns true if rng excludes its end value.

[Source]

/*
 *  call-seq:
 *     rng.exclude_end?    => true or false
 *  
 *  Returns <code>true</code> if <i>rng</i> excludes its end value.
 */

static VALUE
range_exclude_end_p(range)
    VALUE range;
{
    return EXCL(range) ? Qtrue : Qfalse;
}

Returns the first object in rng.

[Source]

/*
 *  call-seq:
 *     rng.first    => obj
 *     rng.begin    => obj
 *  
 *  Returns the first object in <i>rng</i>.
 */

static VALUE
range_first(range)
    VALUE range;
{
    return rb_ivar_get(range, id_beg);
}

Generate a hash value such that two ranges with the same start and end points, and the same value for the "exclude end" flag, generate the same hash value.

[Source]

/*
 * call-seq:
 *   rng.hash    => fixnum
 *
 * Generate a hash value such that two ranges with the same start and
 * end points, and the same value for the "exclude end" flag, generate
 * the same hash value.
 */

static VALUE
range_hash(range)
    VALUE range;
{
    long hash = EXCL(range);
    VALUE v;

    v = rb_hash(rb_ivar_get(range, id_beg));
    hash ^= v << 1;
    v = rb_hash(rb_ivar_get(range, id_end));
    hash ^= v << 9;
    hash ^= EXCL(range) << 24;

    return LONG2FIX(hash);
}

Returns true if obj is an element of rng, false otherwise. Conveniently, === is the comparison operator used by case statements.

   case 79
   when 1..50   then   print "low\n"
   when 51..75  then   print "medium\n"
   when 76..100 then   print "high\n"
   end

produces:

   high

[Source]

/*
 *  call-seq:
 *     rng === obj       =>  true or false
 *     rng.member?(val)  =>  true or false
 *     rng.include?(val) =>  true or false
 *  
 *  Returns <code>true</code> if <i>obj</i> is an element of
 *  <i>rng</i>, <code>false</code> otherwise. Conveniently,
 *  <code>===</code> is the comparison operator used by
 *  <code>case</code> statements.
 *     
 *     case 79
 *     when 1..50   then   print "low\n"
 *     when 51..75  then   print "medium\n"
 *     when 76..100 then   print "high\n"
 *     end
 *     
 *  <em>produces:</em>
 *     
 *     high
 */

static VALUE
range_include(range, val)
    VALUE range, val;
{
    VALUE beg, end;

    beg = rb_ivar_get(range, id_beg);
    end = rb_ivar_get(range, id_end);
    if (r_le(beg, val)) {
        if (EXCL(range)) {
            if (r_lt(val, end)) return Qtrue;
        }
        else {
            if (r_le(val, end)) return Qtrue;
        }
    }
    return Qfalse;
}

Convert this range object to a printable form (using inspect to convert the start and end objects).

[Source]

/*
 * call-seq:
 *   rng.inspect  => string
 *
 * Convert this range object to a printable form (using 
 * <code>inspect</code> to convert the start and end
 * objects).
 */


static VALUE
range_inspect(range)
    VALUE range;
{
    VALUE str, str2;

    str = rb_inspect(rb_ivar_get(range, id_beg));
    str2 = rb_inspect(rb_ivar_get(range, id_end));
    str = rb_str_dup(str);
    rb_str_cat(str, "...", EXCL(range)?3:2);
    rb_str_append(str, str2);
    OBJ_INFECT(str, str2);

    return str;
}

Returns the object that defines the end of rng.

   (1..10).end    #=> 10
   (1...10).end   #=> 10

[Source]

/*
 *  call-seq:
 *     rng.end    => obj
 *     rng.last   => obj
 *  
 *  Returns the object that defines the end of <i>rng</i>.
 *     
 *     (1..10).end    #=> 10
 *     (1...10).end   #=> 10
 */


static VALUE
range_last(range)
    VALUE range;
{
    return rb_ivar_get(range, id_end);
}

Returns true if obj is an element of rng, false otherwise. Conveniently, === is the comparison operator used by case statements.

   case 79
   when 1..50   then   print "low\n"
   when 51..75  then   print "medium\n"
   when 76..100 then   print "high\n"
   end

produces:

   high

[Source]

/*
 *  call-seq:
 *     rng === obj       =>  true or false
 *     rng.member?(val)  =>  true or false
 *     rng.include?(val) =>  true or false
 *  
 *  Returns <code>true</code> if <i>obj</i> is an element of
 *  <i>rng</i>, <code>false</code> otherwise. Conveniently,
 *  <code>===</code> is the comparison operator used by
 *  <code>case</code> statements.
 *     
 *     case 79
 *     when 1..50   then   print "low\n"
 *     when 51..75  then   print "medium\n"
 *     when 76..100 then   print "high\n"
 *     end
 *     
 *  <em>produces:</em>
 *     
 *     high
 */

static VALUE
range_include(range, val)
    VALUE range, val;
{
    VALUE beg, end;

    beg = rb_ivar_get(range, id_beg);
    end = rb_ivar_get(range, id_end);
    if (r_le(beg, val)) {
        if (EXCL(range)) {
            if (r_lt(val, end)) return Qtrue;
        }
        else {
            if (r_le(val, end)) return Qtrue;
        }
    }
    return Qfalse;
}

Iterates over rng, passing each nth element to the block. If the range contains numbers, n is added for each iteration. Otherwise step invokes succ to iterate through range elements. The following code uses class Xs, which is defined in the class-level documentation.

   range = Xs.new(1)..Xs.new(10)
   range.step(2) {|x| puts x}
   range.step(3) {|x| puts x}

produces:

    1 x
    3 xxx
    5 xxxxx
    7 xxxxxxx
    9 xxxxxxxxx
    1 x
    4 xxxx
    7 xxxxxxx
   10 xxxxxxxxxx

[Source]

/*
 *  call-seq:
 *     rng.step(n=1) {| obj | block }    => rng
 *  
 *  Iterates over <i>rng</i>, passing each <i>n</i>th element to the block. If
 *  the range contains numbers, <i>n</i> is added for each iteration.  Otherwise
 *  <code>step</code> invokes <code>succ</code> to iterate through range
 *  elements. The following code uses class <code>Xs</code>, which is defined
 *  in the class-level documentation.
 *     
 *     range = Xs.new(1)..Xs.new(10)
 *     range.step(2) {|x| puts x}
 *     range.step(3) {|x| puts x}
 *     
 *  <em>produces:</em>
 *     
 *      1 x
 *      3 xxx
 *      5 xxxxx
 *      7 xxxxxxx
 *      9 xxxxxxxxx
 *      1 x
 *      4 xxxx
 *      7 xxxxxxx
 *     10 xxxxxxxxxx
 */


static VALUE
range_step(argc, argv, range)
    int argc;
    VALUE *argv;
    VALUE range;
{
    VALUE b, e, step, tmp;

    RETURN_ENUMERATOR(range, argc, argv);

    b = rb_ivar_get(range, id_beg);
    e = rb_ivar_get(range, id_end);
    if (argc == 0) {
        step = INT2FIX(1);
    }
    else {
        rb_scan_args(argc, argv, "01", &step);
        if (!rb_obj_is_kind_of(step, rb_cNumeric)) {
            step = rb_to_int(step);
        }
        if (rb_funcall(step, '<', 1, INT2FIX(0))) {
            rb_raise(rb_eArgError, "step can't be negative");
        }
        else if (!rb_funcall(step, '>', 1, INT2FIX(0))) {
            rb_raise(rb_eArgError, "step can't be 0");
        }
    }

    if (FIXNUM_P(b) && FIXNUM_P(e) && FIXNUM_P(step)) { /* fixnums are special */
        long end = FIX2LONG(e);
        long i, unit = FIX2LONG(step);

        if (!EXCL(range))
            end += 1;
        i = FIX2LONG(b);       
        while (i < end) {
            rb_yield(LONG2NUM(i));
            if (i + unit < i) break;
            i += unit;
        }

    }
    else if (rb_obj_is_kind_of(b, rb_cNumeric) ||
             !NIL_P(rb_check_to_integer(b, "to_int")) ||
             !NIL_P(rb_check_to_integer(e, "to_int"))) {
        ID op = EXCL(range) ? '<' : rb_intern("<=");

        while (RTEST(rb_funcall(b, op, 1, e))) {
            rb_yield(b);
            b = rb_funcall(b, '+', 1, step);
        }
    }
    else {
        tmp = rb_check_string_type(b);

        if (!NIL_P(tmp)) {
            VALUE args[5], iter[2];

            b = tmp;
            args[0] = e;
            args[1] = EXCL(range) ? Qtrue : Qfalse;
            iter[0] = INT2FIX(1);
            iter[1] = step;
            rb_block_call(b, rb_intern("upto"), 2, args, step_i, (VALUE)iter);
        }
        else if (rb_obj_is_kind_of(b, rb_cNumeric) ||
                 !NIL_P(rb_check_to_integer(b, "to_int")) ||
                 !NIL_P(rb_check_to_integer(e, "to_int"))) {
            ID c = EXCL(range) ? '<' : rb_intern("<=");

            while (RTEST(rb_funcall(b, c, 1, e))) {
                rb_yield(b);
                b = rb_funcall(b, '+', 1, step);
            }
        }
        else {
            VALUE args[2];

            if (!rb_respond_to(b, id_succ)) {
                rb_raise(rb_eTypeError, "can't iterate from %s",
                         rb_obj_classname(b));
            }
            args[0] = INT2FIX(1);
            args[1] = step;
            range_each_func(range, step_i, b, e, args);
        }
    }
    return range;
}

Convert this range object to a printable form.

[Source]

/*
 * call-seq:
 *   rng.to_s   => string
 *
 * Convert this range object to a printable form.
 */

static VALUE
range_to_s(range)
    VALUE range;
{
    VALUE str, str2;

    str = rb_obj_as_string(rb_ivar_get(range, id_beg));
    str2 = rb_obj_as_string(rb_ivar_get(range, id_end));
    str = rb_str_dup(str);
    rb_str_cat(str, "...", EXCL(range)?3:2);
    rb_str_append(str, str2);
    OBJ_INFECT(str, str2);

    return str;
}

[Validate]