tpl/math: Add math.Rand template function

Closes #11833
This commit is contained in:
Joe Mooring 2023-12-28 14:25:29 -08:00 committed by Bjørn Erik Pedersen
parent 9cd8fbb332
commit e40b9fbbcf
5 changed files with 71 additions and 6 deletions

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@ -0,0 +1,44 @@
---
title: math.Rand
description: Returns a pseudo-random number in the half-open interval [0.0, 1.0).
categories: []
keywords: []
action:
aliases: []
related: []
returnType: float64
signatures: [math.Rand]
---
The `math.Rand` function returns a pseudo-random number in the [half-open interval] [0.0, 1.0).
```go-html-template
{{ math.Rand }} → 0.6312770459590062
```
To generate a random integer in the [closed interval] [0, 5]:
```go-html-template
{{ math.Rand | mul 6 | math.Floor }}
```
To generate a random integer in the closed interval [1, 6]:
```go-html-template
{{ math.Rand | mul 6 | math.Ceil }}
```
To generate a random float, with one digit after the decimal point, in the closed interval [0, 4.9]:
```go-html-template
{{ div (math.Rand | mul 50 | math.Floor) 10 }}
```
To generate a random float, with one digit after the decimal point, in the closed interval [0.1, 5.0]:
```go-html-template
{{ div (math.Rand | mul 50 | math.Ceil) 10 }}
```
[closed interval]: /getting-started/glossary/#interval
[half-open interval]: /getting-started/glossary/#interval

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@ -147,6 +147,16 @@ A numeric data type without a fractional component. For example, `42`.
Software design and development efforts that enable [localization](#localization). See the [W3C definition](https://www.w3.org/International/questions/qa-i18n). Abbreviated i18n.
###### interval
An [interval](https://en.wikipedia.org/wiki/Interval_(mathematics)) is a range of numbers between two endpoints: closed, open, or half-open.
- A _closed_ interval, denoted by brackets, includes its endpoints. For example, [0,&nbsp;1]&nbsp;is the interval where `0 <= x <= 1`.
- An _open_ interval, denoted by parenthesis, excludes its endpoints. For example, (0,&nbsp;1)&nbsp;is the interval where `0 < x < 1`.
- A _half-open_ interval includes only one of its endpoints. For example, (0,&nbsp;1]&nbsp;is the _left-open_ interval where `0 < x <= 1`, while [0,&nbsp;1)&nbsp;is the _right-open_ interval where `0 <= x < 1`.
###### kind
See [page kind](#page-kind).

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@ -115,6 +115,13 @@ func init() {
},
)
ns.AddMethodMapping(ctx.Rand,
nil,
[][2]string{
{"{{ math.Rand }}", "0.6312770459590062"},
},
)
ns.AddMethodMapping(ctx.Round,
nil,
[][2]string{

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@ -18,6 +18,7 @@ import (
"errors"
"fmt"
"math"
"math/rand"
"reflect"
"sync/atomic"
@ -157,6 +158,11 @@ func (ns *Namespace) Pow(n1, n2 any) (float64, error) {
return math.Pow(af, bf), nil
}
// Rand returns, as a float64, a pseudo-random number in the half-open interval [0.0,1.0).
func (ns *Namespace) Rand() float64 {
return rand.Float64()
}
// Round returns the integer nearest to n, rounding half away from zero.
func (ns *Namespace) Round(n any) (float64, error) {
xf, err := cast.ToFloat64E(n)

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@ -61,12 +61,10 @@ title: "**BatMan**"
ns := nsf(d)
for _, mm := range ns.MethodMappings {
for _, example := range mm.Examples {
if strings.Contains(example[0], "errorf") {
// This will fail the build, so skip for now.
continue
}
if strings.Contains(example[0], "transform.XMLEscape") {
// This will fail the build, so skip for now.
// These will fail the build, so skip.
if strings.Contains(example[0], "errorf") ||
strings.Contains(example[0], "transform.XMLEscape") ||
strings.Contains(example[0], "math.Rand") {
continue
}
templates = append(templates, example[0])