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Class: Enumerator::ArithmeticSequence

Relationships & Source Files
Super Chains via Extension / Inclusion / Inheritance
Class Chain:
self, ::Enumerator
Instance Chain:
self, ::Enumerator, ::Enumerable
Inherits: Enumerator
Defined in: enumerator.c,
enumerator.c

Overview

ArithmeticSequence is a subclass of ::Enumerator, that is a representation of sequences of numbers with common difference. Instances of this class can be generated by the Range#step and Numeric#step methods.

The class can be used for slicing ::Array (see Array#slice) or custom collections.

Class Method Summary

::Enumerator - Inherited

.new

Creates a new ::Enumerator object, which can be used as an ::Enumerable.
.produce

Creates an infinite enumerator from any block, just called over and over.

Instance Attribute Summary

Instance Method Summary

::Enumerator - Inherited

#+

Returns an enumerator object generated from this enumerator and a given enumerable.
#each

Iterates over the block according to how this ::Enumerator was constructed.
#each_with_index

Same as #with_index(0), i.e. there is no starting offset.
#each_with_object

Alias for #with_object.
#feed

Sets the value to be returned by the next yield inside e.
#inspect

Creates a printable version of e.
#next

Returns the next object in the enumerator, and move the internal position forward.
#next_values

Returns the next object as an array in the enumerator, and move the internal position forward.
#peek

Returns the next object in the enumerator, but doesn’t move the internal position forward.
#peek_values

Returns the next object as an array, similar to #next_values, but doesn’t move the internal position forward.
#rewind

Rewinds the enumeration sequence to the beginning.
#size

Returns the size of the enumerator, or nil if it can’t be calculated lazily.
#with_index

Iterates the given block for each element with an index, which starts from offset.
#with_object

Iterates the given block for each element with an arbitrary object, obj, and returns obj
#initialize_copy

::Enumerable - Included

#all?

Passes each element of the collection to the given block.
#any?

Passes each element of the collection to the given block.
#chain

Returns an enumerator object generated from this enumerator and given enumerables.
#chunk

Enumerates over the items, chunking them together based on the return value of the block.
#chunk_while

Creates an enumerator for each chunked elements.
#collect

Alias for Enumerable#map.
#collect_concat

Alias for Enumerable#flat_map.
#count

Returns the number of items in enum through enumeration.
#cycle

Calls block for each element of enum repeatedly n times or forever if none or nil is given.
#detect

Alias for Enumerable#find.
#drop

Drops first n elements from enum, and returns rest elements in an array.
#drop_while

Drops elements up to, but not including, the first element for which the block returns nil or false and returns an array containing the remaining elements.
#each_cons

Iterates the given block for each array of consecutive <n> elements.
#each_entry

Calls block once for each element in self, passing that element as a parameter, converting multiple values from yield to an array.
#each_slice

Iterates the given block for each slice of <n> elements.
#each_with_index

Calls block with two arguments, the item and its index, for each item in enum.
#each_with_object

Iterates the given block for each element with an arbitrary object given, and returns the initially given object.
#entries

Alias for Enumerable#to_a.
#filter

Returns an array containing all elements of enum for which the given block returns a true value.
#filter_map

Returns a new array containing the truthy results (everything except false or nil) of running the block for every element in enum.
#find

Passes each entry in enum to block.
#find_all

Alias for Enumerable#filter.
#find_index

Compares each entry in enum with value or passes to block.
#first

Returns the first element, or the first n elements, of the enumerable.
#flat_map

Returns a new array with the concatenated results of running block once for every element in enum.
#grep

Returns an array of every element in enum for which Pattern === element.
#grep_v

Inverted version of Enumerable#grep.
#group_by

Groups the collection by result of the block.
#include?

Alias for Enumerable#member?.
#inject

Combines all elements of enum by applying a binary operation, specified by a block or a symbol that names a method or operator.
#lazy

Returns an Lazy, which redefines most ::Enumerable methods to postpone enumeration and enumerate values only on an as-needed basis.
#map

Returns a new array with the results of running block once for every element in enum.
#max

Returns the object in enum with the maximum value.
#max_by

Returns the object in enum that gives the maximum value from the given block.
#member?

Returns true if any member of enum equals obj.
#min

Returns the object in enum with the minimum value.
#min_by

Returns the object in enum that gives the minimum value from the given block.
#minmax

Returns a two element array which contains the minimum and the maximum value in the enumerable.
#minmax_by

Returns a two element array containing the objects in enum that correspond to the minimum and maximum values respectively from the given block.
#none?

Passes each element of the collection to the given block.
#one?

Passes each element of the collection to the given block.
#partition

Returns two arrays, the first containing the elements of enum for which the block evaluates to true, the second containing the rest.
#reduce

Alias for Enumerable#inject.
#reject

Returns an array for all elements of enum for which the given block returns false.
#reverse_each

Builds a temporary array and traverses that array in reverse order.
#select

Alias for Enumerable#filter.
#slice_after

Creates an enumerator for each chunked elements.
#slice_before

Creates an enumerator for each chunked elements.
#slice_when

Creates an enumerator for each chunked elements.
#sort

Returns an array containing the items in enum sorted.
#sort_by

Sorts enum using a set of keys generated by mapping the values in enum through the given block.
#sum

Returns the sum of elements in an ::Enumerable.
#take

Returns first n elements from enum.
#take_while

Passes elements to the block until the block returns nil or false, then stops iterating and returns an array of all prior elements.
#tally

Tallies the collection, i.e., counts the occurrences of each element.
#to_a

Returns an array containing the items in enum.
#to_h

Returns the result of interpreting enum as a list of [key, value] pairs.
#uniq

Returns a new array by removing duplicate values in self.
#zip

Takes one element from enum and merges corresponding elements from each args.

Constructor Details

This class inherits a constructor from Enumerator

Instance Attribute Details

#exclude_end? ⇒ Boolean (readonly)

[ GitHub ]

Instance Method Details

#==(obj) ⇒ Boolean Also known as: #===, #eql?

Returns true only if obj is an ArithmeticSequence, has equivalent begin, end, step, and exclude_end? settings.

[ GitHub ] 

  


# File 'enumerator.c', line 3816



static VALUE
arith_seq_eq(VALUE self, VALUE other)
{
    if (!RTEST(rb_obj_is_kind_of(other, rb_cArithSeq))) {
        return Qfalse;
    }

    if (!rb_equal(arith_seq_begin(self), arith_seq_begin(other))) {
        return Qfalse;
    }

    if (!rb_equal(arith_seq_end(self), arith_seq_end(other))) {
        return Qfalse;
    }

    if (!rb_equal(arith_seq_step(self), arith_seq_step(other))) {
        return Qfalse;
    }

    if (arith_seq_exclude_end_p(self) != arith_seq_exclude_end_p(other)) {
        return Qfalse;
    }

    return Qtrue;
}


  








  

    

      #==(obj)  ⇒ Boolean 
      #===(obj)  ⇒ Boolean 
    

  



  

    

Alias for #==.


  





  








  

    #begin  
  

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    #end  
  

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      #==(obj)  ⇒ Boolean 
      #eql?(obj)  ⇒ Boolean 
    

  



  

    

Alias for #==.


  





  








  

    

      #first  ⇒ Numeric? 
      #first(n)  ⇒ Array 
    

  



  

    

Returns the first number in this arithmetic sequence, or an array of the first n elements.


  





  


  [ GitHub ]


  

  


# File 'enumerator.c', line 3457



static VALUE
arith_seq_first(int argc, VALUE *argv, VALUE self)
{
    VALUE b, e, s, ary;
    long n;
    int x;

    rb_check_arity(argc, 0, 1);

    b = arith_seq_begin(self);
    e = arith_seq_end(self);
    s = arith_seq_step(self);
    if (argc == 0) {
        if (NIL_P(b)) {
            return Qnil;
        }
        if (!NIL_P(e)) {
            VALUE zero = INT2FIX(0);
            int r = rb_cmpint(rb_num_coerce_cmp(s, zero, idCmp), s, zero);
            if (r > 0 && RTEST(rb_funcall(b, '>', 1, e))) {
                return Qnil;
            }
            if (r < 0 && RTEST(rb_funcall(b, '<', 1, e))) {
                return Qnil;
            }
        }
        return b;
    }

    // TODO: the following code should be extracted as arith_seq_take

    n = NUM2LONG(argv[0]);
    if (n < 0) {
        rb_raise(rb_eArgError, "attempt to take negative size");
    }
    if (n == 0) {
        return rb_ary_new_capa(0);
    }

    x = arith_seq_exclude_end_p(self);

    if (FIXNUM_P(b) && NIL_P(e) && FIXNUM_P(s)) {
        long i = FIX2LONG(b), unit = FIX2LONG(s);
        ary = rb_ary_new_capa(n);
        while (n > 0 && FIXABLE(i)) {
            rb_ary_push(ary, LONG2FIX(i));
            i += unit;  // FIXABLE + FIXABLE never overflow;
            --n;
        }
        if (n > 0) {
            b = LONG2NUM(i);
            while (n > 0) {
                rb_ary_push(ary, b);
                b = rb_big_plus(b, s);
                --n;
            }
        }
        return ary;
    }
    else if (FIXNUM_P(b) && FIXNUM_P(e) && FIXNUM_P(s)) {
        long i = FIX2LONG(b);
        long end = FIX2LONG(e);
        long unit = FIX2LONG(s);
        long len;

        if (unit >= 0) {
            if (!x) end += 1;

            len = end - i;
            if (len < 0) len = 0;
            ary = rb_ary_new_capa((n < len) ? n : len);
            while (n > 0 && i < end) {
                rb_ary_push(ary, LONG2FIX(i));
                if (i + unit < i) break;
                i += unit;
                --n;
            }
        }
        else {
            if (!x) end -= 1;

            len = i - end;
            if (len < 0) len = 0;
            ary = rb_ary_new_capa((n < len) ? n : len);
            while (n > 0 && i > end) {
                rb_ary_push(ary, LONG2FIX(i));
                if (i + unit > i) break;
                i += unit;
                --n;
            }
        }
        return ary;
    }
    else if (RB_FLOAT_TYPE_P(b) || RB_FLOAT_TYPE_P(e) || RB_FLOAT_TYPE_P(s)) {
        /* generate values like ruby_float_step */

        double unit = NUM2DBL(s);
        double beg = NUM2DBL(b);
        double end = NIL_P(e) ? (unit < 0 ? -1 : 1)*HUGE_VAL : NUM2DBL(e);
        double len = ruby_float_step_size(beg, end, unit, x);
        long i;

        if (n > len)
            n = (long)len;

        if (isinf(unit)) {
            if (len > 0) {
                ary = rb_ary_new_capa(1);
                rb_ary_push(ary, DBL2NUM(beg));
            }
            else {
                ary = rb_ary_new_capa(0);
            }
        }
        else if (unit == 0) {
            VALUE val = DBL2NUM(beg);
            ary = rb_ary_new_capa(n);
            for (i = 0; i < len; ++i) {
                rb_ary_push(ary, val);
            }
        }
        else {
            ary = rb_ary_new_capa(n);
            for (i = 0; i < n; ++i) {
                double d = i*unit+beg;
                if (unit >= 0 ? end < d : d < end) d = end;
                rb_ary_push(ary, DBL2NUM(d));
            }
        }

        return ary;
    }

    return rb_call_super(argc, argv);
}


  








  

    #hash  ⇒ Integer   



  

    

Compute a hash-value for this arithmetic sequence. Two arithmetic sequences with same begin, end, step, and exclude_end? values will generate the same hash-value.



See also Object#hash.


  



  [ GitHub ]


  

  


# File 'enumerator.c', line 3852



static VALUE
arith_seq_hash(VALUE self)
{
    st_index_t hash;
    VALUE v;

    hash = rb_hash_start(arith_seq_exclude_end_p(self));
    v = rb_hash(arith_seq_begin(self));
    hash = rb_hash_uint(hash, NUM2LONG(v));
    v = rb_hash(arith_seq_end(self));
    hash = rb_hash_uint(hash, NUM2LONG(v));
    v = rb_hash(arith_seq_step(self));
    hash = rb_hash_uint(hash, NUM2LONG(v));
    hash = rb_hash_end(hash);

    return ST2FIX(hash);
}


  








  

    

      #last  ⇒ Numeric? 
      #last(n)  ⇒ Array 
    

  



  

    

Returns the last number in this arithmetic sequence, or an array of the last n elements.


  





  


  [ GitHub ]


  

  


# File 'enumerator.c', line 3683



static VALUE
arith_seq_last(int argc, VALUE *argv, VALUE self)
{
    VALUE b, e, s, len_1, len, last, nv, ary;
    int last_is_adjusted;
    long n;

    e = arith_seq_end(self);
    if (NIL_P(e)) {
        rb_raise(rb_eRangeError,
                 "cannot get the last element of endless arithmetic sequence");
    }

    b = arith_seq_begin(self);
    s = arith_seq_step(self);

    len_1 = num_idiv(num_minus(e, b), s);
    if (rb_num_negative_int_p(len_1)) {
        if (argc == 0) {
            return Qnil;
        }
        return rb_ary_new_capa(0);
    }

    last = num_plus(b, num_mul(s, len_1));
    if ((last_is_adjusted = arith_seq_exclude_end_p(self) && rb_equal(last, e))) {
        last = num_minus(last, s);
    }

    if (argc == 0) {
        return last;
    }

    if (last_is_adjusted) {
        len = len_1;
    }
    else {
        len = rb_int_plus(len_1, INT2FIX(1));
    }

    rb_scan_args(argc, argv, "1", &nv);
    if (!RB_INTEGER_TYPE_P(nv)) {
        nv = rb_to_int(nv);
    }
    if (RTEST(rb_int_gt(nv, len))) {
        nv = len;
    }
    n = NUM2LONG(nv);
    if (n < 0) {
        rb_raise(rb_eArgError, "negative array size");
    }

    ary = rb_ary_new_capa(n);
    b = rb_int_minus(last, rb_int_mul(s, nv));
    while (n) {
        b = rb_int_plus(b, s);
        rb_ary_push(ary, b);
        --n;
    }

    return ary;
}


  








  

    #step  
  

  [ GitHub ]