Hi,
use tableName[["columnName"]] without quotes, e.g.
tableName[[columnName]] # see ?"[["
and indexing is done via
x<-length(tableName[[columnName]][tableName[[columnName]] > 6] )
but you may consider
x<-sum(tableName[[columnName]]>6)
which saves some time and typing
Hth.
Am 27.07.2011 17:22, schrieb Lin, YunHui:
> Hi all,
>
> I've been having trouble with something that seems like it should be
> fairly straight forward. Any help at all from more experienced users is
> appreciated!
>
>
>
> I'd like to write a function that uses a column name as an argument.
> However, I run into problems when I try to reference this column within
> the function.
>
> For example,
>
>
>
> findCutoff <- function(tableName, columnName) {
>
>
>
> temporaryTable <- subset(tableName, select = c(V1, V4,
> columnName))
>
>
>
> x <- length(tableName$columnName [tableName$columnName >
> 6] )
>
>
>
> ...etc.
>
> }
>
>
>
> I know a couple of ways to reference a column:
>
> 1. tableName$columnName
>
> 2. tableName[["columnName"]]
>
> I tried turning the function arguments into a string like
> "tableName$columnName" to use within my function, but unfortunately that
> didn't work. With the second method I run into problems if I want to
> compute something like x in the example function above.
>
>
>
> Any ideas, suggestions to try?
>
>
>
> Thanks in advance for any responses!
>
>
>
> YunHui Lisa Lin
> Intern, Customer Intelligence & Web Analytics
>
> Moody's Corporation
> yunhui....@moodys.com <mailto:heather.andr...@moodys.com>
>
>
>
>
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