[R] choosing multiple columns

[Ista Zahn]

On Sat, Aug 11, 2012 at 8:51 AM, Sachinthaka Abeywardana
<sachin.abeywardana at gmail.com> wrote:
> I should have mentioned that I do not know the number index of the columns,
> but regardless, thanks for the responses

Right, so use my first method. This does not depend on the position of
the columns.

Best,
Ista

>
>
> On Sat, Aug 11, 2012 at 10:46 PM, Ista Zahn <istazahn at gmail.com> wrote:
>>
>> Hi Sachin,
>>
>> There are at least two ways. The safer way is to use a regular
>> expression to find the matching columns, like this:
>>
>> a <- initial_data[grep("^OFB[0-9]+", names(initial_data))]
>>
>> Alternatively, if you know that the columns you want are the first 8
>> you can select them by position, like this:
>>
>> a <- initial_data[1:8]
>>
>> Best,
>> Ista
>>
>> On Sat, Aug 11, 2012 at 7:59 AM, Sachinthaka Abeywardana
>> <sachin.abeywardana at gmail.com> wrote:
>> > Hi all,
>> >
>> > I have a data frame that has the columns OFB1, OFB2, OFB3,... OFB10.
>> >
>> > How do I select the first 8 columns efficiently without typing each and
>> > every one of them. i.e. I want something like:
>> >
>> > a<-data.frame(initial_data$OFB1-10) #i know this is wrong, what would be
>> > the correct syntax?
>> >
>> > Thanks,
>> > Sachin
>> >
>> >         [[alternative HTML version deleted]]
>> >
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>