method

zip

v1_8_7_72 - Show latest stable - 3 notes - Class: Array

zip(...) public

Converts any arguments to arrays, then merges elements of self with corresponding elements from each argument. This generates a sequence of self.size n-element arrays, where n is one more that the count of arguments. If the size of any argument is less than enumObj.size, nil values are supplied. If a block given, it is invoked for each output array, otherwise an array of arrays is returned.

   a = [ 4, 5, 6 ]
   b = [ 7, 8, 9 ]

   [1,2,3].zip(a, b)      #=> [[1, 4, 7], [2, 5, 8], [3, 6, 9]]
   [1,2].zip(a,b)         #=> [[1, 4, 7], [2, 5, 8]]
   a.zip([1,2],[8])       #=> [[4,1,8], [5,2,nil], [6,nil,nil]]

Show source

/*
 *  call-seq:
 *     array.zip(arg, ...)                   -> an_array
 *     array.zip(arg, ...) {| arr | block }  -> nil
 *  
 *  Converts any arguments to arrays, then merges elements of
 *  <i>self</i> with corresponding elements from each argument. This
 *  generates a sequence of <code>self.size</code> <em>n</em>-element
 *  arrays, where <em>n</em> is one more that the count of arguments. If
 *  the size of any argument is less than <code>enumObj.size</code>,
 *  <code>nil</code> values are supplied. If a block given, it is
 *  invoked for each output array, otherwise an array of arrays is
 *  returned.
 *     
 *     a = [ 4, 5, 6 ]
 *     b = [ 7, 8, 9 ]
 *     
 *     [1,2,3].zip(a, b)      #=> [[1, 4, 7], [2, 5, 8], [3, 6, 9]]
 *     [1,2].zip(a,b)         #=> [[1, 4, 7], [2, 5, 8]]
 *     a.zip([1,2],[8])       #=> [[4,1,8], [5,2,nil], [6,nil,nil]]
 */

static VALUE
rb_ary_zip(argc, argv, ary)
    int argc;
    VALUE *argv;
    VALUE ary;
{
    int i, j;
    long len;
    VALUE result;

    for (i=0; i<argc; i++) {
        argv[i] = to_ary(argv[i]);
    }
    if (rb_block_given_p()) {
        for (i=0; i<RARRAY(ary)->len; i++) {
            VALUE tmp = rb_ary_new2(argc+1);

            rb_ary_push(tmp, rb_ary_elt(ary, i));
            for (j=0; j<argc; j++) {
                rb_ary_push(tmp, rb_ary_elt(argv[j], i));
            }
            rb_yield(tmp);
        }
        return Qnil;
    }
    len = RARRAY(ary)->len;
    result = rb_ary_new2(len);
    for (i=0; i<len; i++) {
        VALUE tmp = rb_ary_new2(argc+1);

        rb_ary_push(tmp, rb_ary_elt(ary, i));
        for (j=0; j<argc; j++) {
            rb_ary_push(tmp, rb_ary_elt(argv[j], i));
        }
        rb_ary_push(result, tmp);
    }
    return result;
}

August 6, 2009

2 thanks

Second example is correct

@taryneast, the second example is correct. The receiver’s #size limits the result’s.

nachokb

May 7, 2009

0 thanks

question?

Shouldn’t the second example be:

[1,2].zip(a,b)         #=> [[1, 4, 7], [2, 5, 8], [nil,6,9]]

??? or am I missing something?

January 22, 2014

0 thanks

re: question?

Nope. Read it again:

> This generates a sequence of self.size n-element arrays

If any of the arguments are longer than the receiver, the elements beyond the receiver’s length are ignored

zip

Related methods

Second example is correct

question?

re: question?