From: Simon Strandgaard <neoneye@...>
Date: 2004-04-12T11:14:16+09:00
Subject: zip block oddities/bug?

When supplying a block to zip, shouldn't you
be able to affect the output produced by #zip ?

No matter what I do it outputs 'nil'.. 

Is this the intented behavier ?

irb(main):020:0> (4..6).zip {|i| p i; nil }
[4]
[5]
[6]
=> nil
irb(main):021:0> (4..6).zip {|i| p i; [] }
[4]
[5]
[6]
=> nil
irb(main):022:0> (4..6).zip {|i| p i; 666 }
[4]
[5]
[6]
=> nil
irb(main):023:0> (4..6).zip(8) {|i| p i; 666 }
TypeError: cannot convert Fixnum into Array
        from (irb):23:in `zip'
        from (irb):23
        from :0
irb(main):024:0> (4..6).zip(8) {|i| p i; nil }
TypeError: cannot convert Fixnum into Array
        from (irb):24:in `zip'
        from (irb):24
        from :0
irb(main):025:0> (4..6).zip([8]) {|i| p i; nil }
[4, 8]
[5, nil]
[6, nil]
=> nil
irb(main):026:0>

Except from the last line, I only get nil outputted
The block is mentioned in RI, but .. 


erver> ri Enumerable.zip
--------------------------------------------------------- Enumerable#zip
     enum.zip(arg, ...)                   => array
     enum.zip(arg, ...) {|arr| block }    => nil
------------------------------------------------------------------------
     Converts any arguments to arrays, then merges elements of _enum_
     with corresponding elements from each argument. This generates a
     sequence of +enum#size+ _n_-element arrays, where _n_ is one more
     that the count of arguments. If the size of any arguemnt is less
     than +enum#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..3).zip(a, b)      #=> [[1, 4, 7], [2, 5, 8], [3, 6, 9]]
        "cat\ndog".zip([1])   #=> [["cat\n", 1], ["dog", nil]]
        (1..3).zip            #=> [[1], [2], [3]]

server>

--
Simon Strandgaard