[R] Select dataframe row containing a digit

Michael Dewey ||@t@ @end|ng |rom dewey@myzen@co@uk
Wed Nov 30 14:15:20 CET 2022

I suspect [[:digit:]] might have done what you want.


On 30/11/2022 13:04, Luigi Marongiu wrote:
> Thank you,
> I have been trying with [:digit:] but did not work. It worked with
> `df$val[grepl('[0-9]', df$val)] = "NUM"`
> On Wed, Nov 30, 2022 at 2:02 PM Ivan Krylov <krylov.r00t using gmail.com> wrote:
>> В Wed, 30 Nov 2022 13:40:50 +0100
>> Luigi Marongiu <marongiu.luigi using gmail.com> пишет:
>>> I am formatting everything to either "POS" and "NEG",
>>> but values entered as number should get the value "NUM".
>>> How do I change such values?
>> Thanks for providing an example!
>> One idea would be to use a regular expression to locate numbers. For
>> example, grepl('[0-9]', df$val) will return a logical vector indexing
>> the rows containing digits. Alternatively, grepl('^[0-9.]+$', df$val,
>> perl = TRUE) will index all strings consisting solely of digits and
>> decimal separators.
>> Another idea would be to parse all of the strings as numbers and filter
>> out those that didn't succeed. Use as.numeric() to perform the parsing,
>> suppressWarnings() to silence the messages telling you that the parsing
>> failed for some of the strings and is.na() to get the logical vector
>> indexing those entries that failed to parse.
>> --
>> Best regards,
>> Ivan


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