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Document that Last panics on empty slices with a clear error message. Add examples for single element and empty slice cases. Related to Issue 13 (PR #41) 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <noreply@anthropic.com>
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| title | date |
|---|---|
| FoldRight | 2025-01-16T00:00:00-00:00 |
FoldRight is like Reduce but processes elements from right to left. Also known as foldr in Haskell. Important for non-associative operations where the order of evaluation matters.
package main
import (
"fmt"
u "github.com/rjNemo/underscore"
)
func main() {
// Subtraction is non-associative
nums := []int{1, 2, 3}
// FoldRight: 1 - (2 - (3 - 0)) = 1 - (2 - 3) = 1 - (-1) = 2
result := u.FoldRight(nums, 0, func(n, acc int) int { return n - acc })
fmt.Println(result) // 2
// Compare with Reduce (left fold): (0 - 1) - 2 - 3 = -6
leftResult := u.Reduce(nums, func(n, acc int) int { return acc - n }, 0)
fmt.Println(leftResult) // -6
// Building a list in order
buildList := u.FoldRight(nums, []int{}, func(n int, acc []int) []int {
return append([]int{n}, acc...)
})
fmt.Println(buildList) // [1, 2, 3]
// String concatenation
words := []string{"a", "b", "c"}
concat := u.FoldRight(words, "", func(s, acc string) string { return s + acc })
fmt.Println(concat) // "abc"
}