View source code
Display the source code in std/algorithm/iteration.d from which this
page was generated on github.
Report a bug
If you spot a problem with this page, click here to create a
Bugzilla issue.
Improve this page
Quickly fork, edit online, and submit a pull request for this page.
Requires a signed-in GitHub account. This works well for small changes.
If you'd like to make larger changes you may want to consider using
local clone.
Function std.algorithm.iteration.mean
Finds the mean (colloquially known as the average) of a range.
T mean(T, R)
(
R r
)
if (isInputRange!R && isNumeric!(ElementType!R) && !isInfinite!R);
auto mean(R, T)
(
R r,
T seed
)
if (isInputRange!R && !isNumeric!(ElementType!R) && is(typeof(r .front + seed)) && is(typeof(r .front / size_t(1))) && !isInfinite!R);
For built-in numerical types, accurate Knuth & Welford mean calculation
is used. For user-defined types, element by element summation is used.
Additionally an extra parameter seed
is needed in order to correctly
seed the summation with the equivalent to 0
.
The first overload of this function will return T
if the range
is empty. However, the second overload will return seed
on empty ranges.
This function is Ο(r
).
Parameters
Name | Description |
---|---|
T | The type of the return value. |
r | An input range |
seed | For user defined types. Should be equivalent to 0 . |
Returns
Example
import std .math .operations : isClose;
import std .math .traits : isNaN;
static immutable arr1 = [1, 2, 3];
static immutable arr2 = [1.5, 2.5, 12.5];
assert(arr1 .mean .isClose(2));
assert(arr2 .mean .isClose(5.5));
assert(arr1[0 .. 0] .mean .isNaN);
Authors
License
Copyright © 1999-2022 by the D Language Foundation | Page generated by ddox.