# whist

##### Weighted Histogram

Computes the weighted histogram of a set of observations with a given set of weights.

- Keywords
- arith

##### Usage

`whist(x, breaks, weights = NULL)`

##### Arguments

- x
- Numeric vector of observed values.
- breaks
- Vector of breakpoints for the histogram.
- weights
- Numeric vector of weights for the observed values.

##### Details

This low-level function computes (but does not plot) the weighted
histogram of a vector of observations `x`

using a given
vector of `weights`

.

The arguments `x`

and `weights`

should be numeric vectors of
equal length. They may include `NA`

or infinite values.

The argument `breaks`

should be a numeric vector whose entries
are strictly increasing. These values define the boundaries between the
successive histogram cells.
The breaks *do not* have to span the range
of the observations.

There are `N-1`

histogram cells, where `N = length(breaks)`

.
An observation `x[i]`

falls in the `j`

th cell if
`breaks[j] <= x[i]="" <="" breaks[j+1]<="" code=""> (for `

`j < N-1`

)
or
`breaks[j] <= x[i]="" <="breaks[j+1] (for `

`j = N-1`

).
The weighted histogram value `h[j]`

for the `j`

th cell is
the sum of `weights[i]`

for all observations `x[i]`

that
fall in the cell.
Note that, in contrast to the function `hist`

,
the function `whist`

does not require the breakpoints to span the
range of the observations `x`

. Values of `x`

that fall outside the
range of `breaks`

are handled separately; their total weight
is returned as an attribute of the histogram.

##### Value

- A numeric vector of length
`N-1`

containing the histogram values, where`N = length(breaks)`

.The return value also has attributes

`"low"`

and`"high"`

giving the total weight of all observations that are less than the lowest breakpoint, or greater than the highest breakpoint, respectively.

##### Examples

```
x <- rnorm(100)
b <- seq(-1,1,length=21)
w <- runif(100)
whist(x,b,w)
```

*Documentation reproduced from package spatstat, version 1.25-1, License: GPL (>= 2)*