[R] iterating over a data frame the R way?

[Gabor Grothendieck]

This iterates functions f over successive rows of mytable:

apply(mytable, 1, f)

or if you want to use SQL on R data frames then see sqldf
http://sqldf.googlecode.com

On Thu, Dec 31, 2009 at 5:52 PM,  <donahchoo at me.com> wrote:
> In this specific case I'm going to do another select, from a different table
> with the where clause being based on the start_time and end_time.
>
> select * from table_name where time >= start_time and time <= end_time;
>
>
> On Dec 31, 2009, at 3:57 PM, John Kane wrote:
>
>> Uh what do you want to do to it/them?
>>
>> Here are a couple of R-type commands on a data.frame.
>>
>> mydata  <- data.frame(vec1 =  seq(19,109, by=10),
>> vec2 =seq(30,120, by=10))
>>
>> mydata[,1]+mydata[,2]
>> apply(mydata, 2, mean)
>>
>>
>>
>> --- On Thu, 12/31/09, donahchoo at me.com <donahchoo at me.com> wrote:
>>
>>> From: donahchoo at me.com <donahchoo at me.com>
>>> Subject: [R] iterating over a data frame the R way?
>>> To: r-help at r-project.org
>>> Received: Thursday, December 31, 2009, 2:44 PM
>>> Hi,
>>>
>>> I have a data frame that was create by issuing a select
>>> against my sqlite database.  I want to get each row
>>> from the data frame and use the each of the column
>>> values.  The data frame looks like this:
>>>
>>> start_time    end_time
>>> 09:30:00      10:00:00
>>> 10:00:01      10:30:00
>>> etc
>>>
>>> Can a point me to a tutorial/example of doing this?  I
>>> the other programming languages I'm familiar with I would
>>> just loop over the frame and access the elements, but I
>>> believe that's not the R way and can't find examples of
>>> doing this.
>>>
>>> Thanks!
>>>
>>> ______________________________________________
>>> R-help at r-project.org
>>> mailing list
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>>> PLEASE do read the posting guide
>>> http://www.R-project.org/posting-guide.html
>>> and provide commented, minimal, self-contained,
>>> reproducible code.
>>>
>>
>>
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> ______________________________________________
> R-help at r-project.org mailing list
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> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>