[R] Numbers in a string

[Gabor Grothendieck]

On Thu, Dec 16, 2010 at 11:42 AM, Petr Savicky <savicky at cs.cas.cz> wrote:
> On Thu, Dec 16, 2010 at 06:17:45AM -0800, Dieter Menne wrote:
>> Petr Savicky wrote:
>> >
>> > One of the suggestions in this thread was to use an external program.
>> > A possible solution without negation in Perl is
>> >
>> >   @a = ("AB15E9SDF654VKBN?dvb.65" =~ m/[0-9]/g);
>> >   print @a, "\n";
>> >   15965465
>> >
>> >
>>
>> Which is
>>
>>  gsub("[^0-9]", "", "AB15E9SDF654VKBN?dvb.65")
>>
>> as Henrique suggested.
>
> I agree. The Perl code was a reply to a question, whether the same can be
> done by describing the required elements and not by describing the ones to
> be removed. This could be useful, if we want to extract elements described
> by a more complex regular expression. A more accurate, although not
> complete and definitely not the best, extraction of nonnegative numbers
> in Perl may be done as follows
>
>  @a = ("abcde. 11 abc 5.31e+34, (1.45)" =~ m/[0-9]+\.[0-9]+e[+-][0-9]+|[0-9]+\.[0-9]+|[0-9]+/g);
>  print join(" ", @a), "\n";
>  11 5.31e+34 1.45
>
> Can something similar be done in R either specifically for numbers or
> for a general regular expression?
>

Dieter's first post in this thread already answered that question.

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