[R] Creating a vector of categories

[Sharpie]

Christoffer Karlsson wrote:
> 
> Hi,
> 
> I have a column in a data frame looking something like:
> 
> $sex $language $count
> male  english  0
> male  english  0
> female  english  32
> male  spanish  154
> female  english  11
> female  norweigan 7
> 
> and so on.
> What I want to do is to order these in to categories, for instance one
> category where count>=0 & count<10 and so on..
> 
> I want my data to turn out looking something like:
> 
> male english 0-10 1324
> male english 11-20 756
> .....
> male spanish 0-10 354
> ...
> female english 0-10 1557
> ...
> 
> and so on, where the right hand is the count of the number of people in
> each
> category.
> Up until now I've been subsetting the data frame into each category, and
> then counting number of rows in each subset. However I now have a large
> amount of different factor combinations which makes this process tedious.
> 
> Any help would be appreciated!
> Chris
> 

You can quickly assign a category to each row in your data frame with the
cut() function:

  testData <- structure(list(sex = structure(c(2L, 2L, 1L, 2L, 1L, 1L, 2L, 
1L, 2L), .Label = c("female", "male"), class = "factor"), language =
structure(c(1L, 
1L, 1L, 3L, 1L, 2L, 3L, 3L, 1L), .Label = c("english", "norweigan", 
"spanish"), class = "factor"), count = c(0L, 0L, 32L, 154L, 11L, 
7L, 3L, 5L, 2L)), .Names = c("sex", "language", "count"), class =
"data.frame", row.names = c(NA, 
-9L))

  binMax <- ceiling( max(testData$count) / 10 ) * 10
  binBreaks <- seq( 0, binMax, by = 10 )

  testData$bin <- cut( testData$count, binBreaks, include.lowest = TRUE )

And then as Petr said:

  with( testData, aggregate(count, list(sex, language, bin), length))


Hope this helps!

-Charlie

-----
Charlie Sharpsteen
Undergraduate-- Environmental Resources Engineering
Humboldt State University
-- 
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