[R] Obtaining midpoints of class intervals produced by cut and table

[Peter Dalgaard]

jose romero wrote:
> Hello list:
> 
> I am using "cut" and "table" to obtain a frequency table from a
numeric sample vector. The idea is to calculate mean and standard
deviation on grouped data. However, I can't extract the midpoints of the
class intervals, which seem to be strings treated as factors. How do i
extract the midpoint?
> 

You might consider starting with hist() instead. Otherwise, how about

mid <- brk[-1] - diff(brk)/2

where brk is the breakpoints used in cut()

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