Message-ID: <77EB52C6DD32BA4D87471DCD70C8D700043B745D@NA-PA-VBE03.na.tibco.com>
Date: 2011-05-17T20:39:07Z
From: William Dunlap
Subject: subsetting a list of dataframes
In-Reply-To: <BANLkTimS73dDE5gCWyY=zxkM03Dpf+3Dew@mail.gmail.com>
shouldKeep <- sapply(listOfDataFrames, function(df)nrow(df)>1)
listOfDataFrames[shouldKeep]
or, compressed to get rid of the intermediate variable
listOfDataFrames[sapply(listOfDataFrames, function(df)nrow(df)>1)]
If you are writing production code and there is any chance that
listOfDataFrames might be an empty list you can use vapply (which
requires that you supply a prototype for FUN's return value):
listOfDataFrames[vapply(listOfDataFrames, function(df)nrow(df)>1,
FUN.VALUE=FALSE)]
Bill Dunlap
Spotfire, TIBCO Software
wdunlap tibco.com
> -----Original Message-----
> From: r-help-bounces at r-project.org
> [mailto:r-help-bounces at r-project.org] On Behalf Of Lara Poplarski
> Sent: Tuesday, May 17, 2011 1:25 PM
> To: r-help at r-project.org
> Subject: [R] subsetting a list of dataframes
>
> Hello All,
>
> I have a list of dataframes, and I need to subset it by
> keeping only those
> dataframes in the list that meet a certain criterion.
> Specifically, I need
> to generate a second list which only includes those
> dataframes whose number
> of rows is > 1.
>
> Could someone suggest how to do this? I have come close to
> what I need with
> loops and such, but there must be a less clumsy way...
>
> Many thanks,
> Lara
>
> [[alternative HTML version deleted]]
>
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