[R] Getting the values out of histogram (lattice)

[Duncan Mackay]

Hi Monica

An example abbreviated from ?histogram

  x = histogram( ~ height, data = singer)

names(x)
# to see what is there
str(x)

# information
x$panel.args.common
$breaks
  [1] 59.36 61.28 63.20 65.12 67.04 68.96 70.88 72.80 74.72 76.64

$type
[1] "percent"

$equal.widths
[1] TRUE

$nint
[1] 9

# x$panel.args: name as number
x[[35]]
[[1]]
[[1]]$x
   [1] 64 62 66 65 60 61 65 66 65 63 67 65 62 65 
68 65 63 65 62 65 66 62 65 63 65 66 65 62 65 66 
65 61 65 66 65 62 63 67 60 67 66 62 65 62
  [45] 61 62 66 60 65 65 61 64 68 64 63 62 64 62 
64 65 60 65 70 63 67 66 65 62 68 67 67 63 67 66 
63 72 62 61 66 64 60 61 66 66 66 62 70 65
  [89] 64 63 65 69 61 66 65 61 63 64 67 66 68 70 
65 65 65 64 66 64 70 63 70 64 63 67 65 63 66 66 
64 64 70 70 66 66 66 69 67 65 69 72 71 66
[133] 76 74 71 66 68 67 70 65 72 70 68 64 73 66 
68 67 64 68 73 69 71 69 76 71 69 71 66 69 71 71 
71 69 70 69 68 70 68 69 72 70 72 69 73 71
[177] 72 68 68 71 66 68 71 73 73 70 68 70 75 68 
71 70 74 70 75 75 69 72 71 70 71 68 70 75 72 66 
72 70 69 72 75 67 75 74 72 72 74 72 72 74
[221] 70 66 68 75 68 70 72 67 70 70 69 72 71 74 75

etc to suite your requirements

HTH

Regards

Duncan


Duncan Mackay
Department of Agronomy and Soil Science
University of New England
ARMIDALE NSW 2351
Email: home mackay at northnet.com.au



At 23:50 31/08/2011, you wrote:



>Hi,
>
>
>
>I have a relatively big dataset and I want to construct
>some histograms using the histogram function in lattice. One thing I am
>interested in is to look at differences between 
>density and percent. I know I can
>use the hist function but it seems that this function gives sometimes some
>wrong answers and the density is actually a 
>percent since it is calculated as counts in the 
>bin divided by the total no. of points. Let me explain.
>
>
>
>If I let the hist function to decide the breaks, or I use
>a small number, or one of the pre-determined methods to select breaks then
>everything seems to be in order. But if I decide to use ­ for example ­ 100 as
>a breaks (I have over 90000 data points so the number of breaks is not
>necessarily too large I would think) the density for the first bin is over 1,
>although for all the other breaks the density is 
>actually a percent since it is
>the count for that bin divided by the total no. 
>of points I have. So 
. Here it
>is something wrong or most probably I am doing something wrong.
>
>
>
>If I use the function histogram from lattice it is
>obvious that there is a difference between the percent param and the density
>param. I looked at the function code and I 
>didn't understand it ­ to be honest.
>It seems it calls inside the hist function, or a slightly modify variant of
>hist. Reading about the object trellis I saw I can access different info about
>the graph it generates but nothing about the actual data that goes into
>defining the histogram. How can I access the data from it?
>
>
>
>I am not sure if my problem is platform specific ­ it should
>not be ­ but I have Rx64 2.13.1 on windows machine, in case it counts.
>
>
>
>I appreciate your help, thanks,
>
>
>
>Monica
>
>
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