Message-ID: <9D3BDD8A-541C-4C9A-8BD7-B7F1A2ED5460@comcast.net>
Date: 2010-01-18T15:23:05Z
From: David Winsemius
Subject: unique: factor to string
In-Reply-To: <431366.20162.qm@web113515.mail.gq1.yahoo.com>
On Jan 18, 2010, at 10:05 AM, Markus M?hlbacher wrote:
> Hi community,
>
> I want to count the occurrence of values within a dataframe.
> data$names is a list of many names.
It's most likely a vector.
> With namelist <- unique(data$names) I get all the existing names.
> But the result is a factor, not a list of strings.
as.character(data$names) # would be a character vector, i.e., a
structure composed of "strings"
# You could make it a list if you wanted, but it's not clear that is
needed for your purposes.
>
> I would then like to go trough all the names in a for-loop and count
> their occurrence.
That shows your C programming background. Try instead the loop-less
method:
table(data$names)
BTW using "names" for an object's name is not a good programing
practice in R because there is a useful function by the same
name. ..... and then there is always the "dog" fortune.
--
David.
>
--
David Winsemius, MD
Heritage Laboratories
West Hartford, CT