[R] pivot table in R

[Christos Hatzis]

Also, see ?aggregate:

> with(A, aggregate(no_of_accidents, by=list(SEX=sex), FUN='sum'))
  SEX  x
1   F 34
2   M 83 

> -----Original Message-----
> From: r-help-bounces at r-project.org 
> [mailto:r-help-bounces at r-project.org] On Behalf Of Attiglah, Mama
> Sent: Tuesday, January 29, 2008 7:21 AM
> To: pietro.parodi at aon.co.uk; r-help at r-project.org
> Subject: Re: [R] pivot table in R
> 
> A = read.table("clipboard", header=TRUE)
> > A
>   sex   age region no_of_accidents
> 1   F young  north              10
> 2   F young  south              12
> 3   F   old  north               5
> 4   F   old  south               7
> 5   M young  north              24
> 6   M young  south              30
> 7   M   old  north              12
> 8   M   old  south              17
> 
> 
> 
> 
> 
> sum(A$no_of_accidents[which( A$sex=="F")])
> 
> should give you the required sum. 
> 
> You have to remember that sex, age and region are Factors 
> with their respective levels and no_of_accidents is a numeric vector.
> 
> Do str( A) to see their type.
> Hope that helps.
> 
> Mama 
> 
> -----
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> -----Original Message-----
> From: r-help-bounces at r-project.org 
> [mailto:r-help-bounces at r-project.org]
> On Behalf Of pietro.parodi at aon.co.uk
> Sent: 29 January 2008 12:05
> To: r-help at r-project.org
> Subject: [R] pivot table in R
> 
> Hello,
> 
> I'm struggling with an elementary problem with R. I have a 
> simple data frame such as this one giving the number of 
> accidents subdivided by sex,
> 
> age and region.
> 
> sex     age     region          no_of_accidents
> 
> F       young   north           10
> F       young   south           12
> F       old     north           5
> F       old     south           7
> M       young   north           24
> M       young   south           30
> M       old     north           12
> M       old     south           17
> 
> and I would like to build a pivot table, e.g. obtaining the 
> sum of the number of accidents for each sex:
> 
> sex     age     region          no_of_accidents
> 
> F       (any)   (any)           34
> M       (any)   (any)           83
> 
> but I can't seem to obtain this result simply in R, except by 
> embarking in complicated "for" loops.
> 
> I have checked the documentation on such functions as 
> "table()" and the documentation on "An introduction to R" but 
> couldn't solve the problem. 
> Could you please help me with this?
> 
> Cheers
> 
> Pete
> 
> 
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