R help - Oct 2010 - Using names function

Just starting on my journey to learn R and the book I am using is "Using R
for Introductory Statistics"

One of the problems (page 15, 1.10) goes as follows:
The monthly sales fig for 2002 were (2700, 2600, 3050, . . ). Using diff() find
the month with greatest increase from prev month.

I created a msales var:
msales = c(2700, 2600, 3050 . . )

I named them:
names(msales)=c("Jan", Feb", "Mar" . . .)

to find the month with greatest increase from prev month:
max(diff(msales))

I get the numeric value displayed when I execute the above function, but not the
month. cumsum(msales) displays the results under each month, but not max. How
can I get both the month and value displayed?

Thanks
-Sudhakar

ps: no, I am not a student seeking answers to exercises :)
 		 	   		  
	[[alternative HTML version deleted]]

Hi Sudhakar,

Take a look at ?which.max

msales <- c(2700, 2600, 3050)
names(msales) <- c("Jan", "Feb", "Mar")
names(which.max(diff(msales)))
# [1] "Mar"

HTH,
Jorge


On Sat, Oct 30, 2010 at 12:27 PM, Sudhakar Kumar <> wrote:
>
> Just starting on my journey to learn R and the book I am using is
"Using R
> for Introductory Statistics"
>
> One of the problems (page 15, 1.10) goes as follows:
> The monthly sales fig for 2002 were (2700, 2600, 3050, . . ). Using diff()
> find the month with greatest increase from prev month.
>
> I created a msales var:
> msales = c(2700, 2600, 3050 . . )
>
> I named them:
> names(msales)=c("Jan", Feb", "Mar" . . .)
>
> to find the month with greatest increase from prev month:
> max(diff(msales))
>
> I get the numeric value displayed when I execute the above function, but
> not the month. cumsum(msales) displays the results under each month, but
not
> max. How can I get both the month and value displayed?
>
> Thanks
> -Sudhakar
>
> ps: no, I am not a student seeking answers to exercises :)
>
>        [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
	[[alternative HTML version deleted]]

On Oct 30, 2010, at 12:27 PM, Sudhakar Kumar wrote:
>
> Just starting on my journey to learn R and the book I am using is  
> "Using R for Introductory Statistics"
>
> One of the problems (page 15, 1.10) goes as follows:
> The monthly sales fig for 2002 were (2700, 2600, 3050, . . ). Using  
> diff() find the month with greatest increase from prev month.
>
> I created a msales var:
> msales = c(2700, 2600, 3050 . . )
>
> I named them:
> names(msales)=c("Jan", Feb", "Mar" . . .)
Get in the habit of copy-pasting from the console. This is not valid  
code.
>
> to find the month with greatest increase from prev month:
> max(diff(msales))
>
> I get the numeric value displayed when I execute the above function,  
> but not the month. cumsum(msales) displays the results under each  
> month, but not max. How can I get both the month and value displayed?
>
 > diff(msales)[which.max(diff(msales))]
Mar
450

-- 

David Winsemius, MD
West Hartford, CT