Where is the percentile function in CRAN -R

I do not understand all t开发者_运维知识库he terminology inside R. I have only 100 level statistics, trying to learn more.

I am guessing R has a built-in percentile function named something I don't recognize or know how to search for.

I can write my own, but rather use the built in one for obvious reasons.

Here's the one I wrote:

percentile <- function(x) return((x - min(x)) / (max(x) - min(x))

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You can do this via

scale(x,center=min(x,na.rm=TRUE),scale=diff(range(x,na.rm=TRUE)))

but I'm not sure there is actually a built-in function that does the scaling you're asking for.

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If you are looking to find out specific percentiles from a data set, take a look at the quantile function: ?quantile. By multiplying by 100, you get percentiles.

If you are looking into converting numbers to their percentiles, take a look at rank, though you will need to determine how to address ties. You can simply rescale from rank to quantile by dividing by the length of the vector.

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The quantile function might be what you are looking for. If you have vector x and you want to know the 25th, 43rd, and 72nd percentiles you would execute this:

quantile(x, c(.25, .43, .72));

The semicolon is, of course, optional.

See http://www.r-tutor.com/elementary-statistics/numerical-measures/percentile

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You can search for functions (or for just about anything else) via RSiteSearch e.g.,

RSiteSearch("percentile")

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On the off chance you are thinking about a percentile based on a distribution, here is a different answer. Each probability distribution has a set of 4 functions associated with it: a density, distribution, quantile, and generating function. These are prefixes of d-, p-, q-, and r-, respectively (with the same suffix based on the distribution). You have a uniform distribution, and are asking about percentiles (distribution) so you want punif. It takes min and max as two of its arguments.

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I made this function function, check it. Data is any vector, row of any matrix o data frame.

percentiles<-function(Data) return(quantile(Data, seq(0,1, by=.01)))