[Bioc-devel] Adding a lengths() method to List class

[Peter Hickey]

Thanks, Michael!

On Fri, 2 Oct 2015 at 13:54 Michael Lawrence <lawrence.michael at gene.com>
wrote:

> Change was made. Should dispatch to length and [[ methods.
>
> On Wed, Sep 30, 2015 at 9:37 PM, Hervé Pagès <hpages at fredhutch.org> wrote:
>
>> On 09/30/2015 05:28 PM, Michael Lawrence wrote:
>>
>>> It wasn't a conscious choice, but it would slow things down a bit. Not
>>> by much though, since we're already attempting dispatch on length(). I
>>> can make the change.
>>>
>>
>> That would be great. Thanks Michael!
>>
>> H.
>>
>>
>>> On Wed, Sep 30, 2015 at 1:33 PM, Hervé Pagès <hpages at fredhutch.org
>>> <mailto:hpages at fredhutch.org>> wrote:
>>>
>>>     Hi Michael,
>>>
>>>     I was expecting this to just work:
>>>
>>>        base::lengths(IntegerList(1:4, 1:6))
>>>
>>>     but it doesn't:
>>>
>>>        Error in base::lengths(IntegerList(1:4, 1:6)) :
>>>          'x' must be a list or atomic vector
>>>
>>>     The man page says:
>>>
>>>           This function loops over ‘x’ and returns a compatible vector
>>>           containing the length of each element in ‘x’.  Effectively,
>>>           ‘length(x[[i]])’ is called for all ‘i’, so any methods on
>>> ‘length’
>>>           are considered.
>>>
>>>     If length(x[[i]]) is called for all i then it should work on any
>>> object
>>>     for which [[ is defined. Note that this is what happens with
>>>     base::sapply(), base::mapply(), etc... they all use [[ internally.
>>>
>>>     Do you know of any reason why lengths() doesn't do this?
>>>
>>>     Thanks,
>>>     H.
>>>
>>>
>>>     On 09/28/2015 09:51 PM, Michael Lawrence wrote:
>>>
>>>         That is the plan. Note that we already have elementLengths()
>>>         that serves
>>>         the same purpose. It was the direct inspiration for lengths().
>>>
>>>         On Mon, Sep 28, 2015 at 9:41 PM, Peter Hickey
>>>         <peter.hickey at gmail.com <mailto:peter.hickey at gmail.com>>
>>>         wrote:
>>>
>>>             The lengths() function was added in R 3.2 to "get the length
>>>             of each
>>>             element of a list or atomic vector (is.atomic) as an integer
>>>             or numeric
>>>             vector." It seems useful to me to have also a similar method
>>>             defined for
>>>             the S4Vectors::List class (and subclasses). What do others
>>>             think?
>>>
>>>                       [[alternative HTML version deleted]]
>>>
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>>>
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>>>
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>>>
>>>
>>>     --
>>>     Hervé Pagès
>>>
>>>     Program in Computational Biology
>>>     Division of Public Health Sciences
>>>     Fred Hutchinson Cancer Research Center
>>>     1100 Fairview Ave. N, M1-B514
>>>     P.O. Box 19024
>>>     Seattle, WA 98109-1024
>>>
>>>     E-mail: hpages at fredhutch.org <mailto:hpages at fredhutch.org>
>>>     Phone: (206) 667-5791 <tel:%28206%29%20667-5791>
>>>     Fax: (206) 667-1319 <tel:%28206%29%20667-1319>
>>>
>>>
>>>
>> --
>> Hervé Pagès
>>
>> Program in Computational Biology
>> Division of Public Health Sciences
>> Fred Hutchinson Cancer Research Center
>> 1100 Fairview Ave. N, M1-B514
>> P.O. Box 19024
>> Seattle, WA 98109-1024
>>
>> E-mail: hpages at fredhutch.org
>> Phone:  (206) 667-5791
>> Fax:    (206) 667-1319
>>
>
>

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