- Returns true if all elements return true for given predicate
All([]int{1, 2, 3, 4, 5}, func(i int)bool {return i < 7})
// true
All([]int{1, 2, 3, 4, 5}, func(i int)bool {return i % 2 == 0})
// false- Returns true if at least one element returns true for given predicate
Any([]int{1, 2, 3}, func(i int)bool {return i%2==0})
// true
Any([]int{1, 2, 3}, func(i int)bool {return i > 7})
// false- Returns a map containing key-value pairs returned by the given function applied to the elements of the given slice
Associate([]int{1, 2, 3, 4}, func(i int) (string, int) {
return fmt.Sprintf("M%d", i), i * 10
})
// {"M1": 10, "M2": 20, "M3": 30, "M4": 40}- Splits the slice into a slice of slices, each not exceeding given chunk size
- The last slice might have fewer elements than the given chunk size
Chunked([]int{1, 2, 3, 4, 5, 6, 7, 8, 9}, 2)
// [[1, 2], [3, 4], [5, 6], [7, 8], [9]]- Returns a slice containing only distinct elements from the given slice
Distinct([]int{1, 1, 2, 3, 3, 4, 4, 4, 4, 5, 5, 5})
// [1, 2, 3, 4, 5]- Returns a slice containing only distinct elements from the given slice as distinguished by the given selector function
DistinctBy([]string{"a", "A", "b", "B", "c", "C"},func(s string) string {
return strings.ToLower(s)
})
// ["a", "b", "c"]- Returns a slice containing all elements except the first n.
// letters = ['a'..'z']
Drop(letters, 23)
// ['x', 'y', 'z']- Returns a slice containing all elements except the last n.
// letters = ['a'..'z']
DropLast(letters, 23)
// ['a', 'b', 'c']- Returns a slice containing all elements except the first elements that satisfy the given predicate.
// letters = ['a'..'z']
DropWhile(letters, func(r rune) bool { return r < 'x' })
// ['x', 'y', 'z']- Returns a slice containing all elements except the last elements that satisfy the given predicate.
// letters = ['a'..'z']
DropLastWhile(letters, func(r rune) bool { return r > 'c' })
// ['a', 'b', 'c']- Returns the slice obtained after retaining only those elements in the given slice for which the given function returns true
Filter([]int{1, 2, 3, 4, 5, 6, 7, 8}, func(i int)bool {return i%2==0})
// [2, 4, 6, 8]- Returns the slice obtained after retaining only those elements in the given slice for which the given function returns true
- Predicate function receives the value as well as its index in the slice.
FilterIndexed([]int{0, 1, 2, 3, 4, 8, 6}, func(index int, v int) bool {
return index == v
})
// [0, 1, 2, 3, 4, 6]- Accumulates values starting with given initial value and applying given function to current accumulator and each element.
Fold([]int{1, 2, 3, 4, 5}, func(acc, v int) int { return acc + v })
// 15- Accumulates values starting with given initial value and applying given function to current accumulator and each element.
- Function also receives index of current element.
FoldIndexed([]int{1, 2, 3, 4, 5}, func(index, acc, v int) int {
return acc + index*v
})
// 40- Returns a map where each key maps to slices of elements all having the same key as returned by the given function
GroupBy([]string{"a", "abc", "ab", "def", "abcd"}, func(s string) int {
return len(s)
})
// {1: ["a"], 2: ["ab"], 3: ["abc", "def"], 4: ["abcd"]},- Returns the slice obtained after applying the given function over every element in the given slice
Map([]int{1, 2, 3, 4, 5}, func(i int) int { return i * i })
// [1, 4, 9, 16, 25]- Returns the slice obtained after applying the given function over every element in the given slice
- The function also receives the index of each element in the slice.
MapIndexed([]int{1, 2, 3, 4, 5}, func(index, i int) int { return index * i })
// [0, 2, 6, 12, 20]- Returns two slices where the first slice contains elements for which the predicate returned true and the second slice contains elements for which it returned false.
type person struct {
name string
age int
}
tom := &person{"Tom", 18}
andy := &person{"Andy", 32}
sarah := &person{"Sarah", 22}
Partition([]*person{tom, andy, sarah}, func(p *person) bool { return p.age < 30 })
// [tom, sarah], [andy]- Accumulates the values starting with the first element and applying the operation from left to right to the current accumulator value and each element.
- The input slice must have at least one element.
Reduce([]int{1, 2, 3, 4, 5}, func(acc, v int) int { return acc + v })
// 15- Accumulates the values starting with the first element and applying the operation from left to right to the current accumulator value and each element.
- The input slice must have at least one element.
- The function also receives the index of each element.
ReduceIndexed([]string{"a", "b", "c", "d"}, func(index int, acc, v string) string {
return fmt.Sprintf("%s%s%d", acc, v, index)
})
// "ab1c2d3"- Reverses the elements of the list in place.
// s = [1, 2, 3, 4, 5, 6, 7]
Reverse(s)
// s = [7, 6, 5, 4, 3, 2, 1]- Returns a new list with the elements in reverse order.
// s = [1, 2, 3, 4, 5, 6, 7]
r := Reversed(s)
// r = [7, 6, 5, 4, 3, 2, 1]
// s = [1, 2, 3, 4, 5, 6, 7] - Returns the slice obtained after taking the first n elements from the given slice.
// letters = ['a'..'z']
Take(letters, 2)
// ['a', 'b']- Returns the slice obtained after taking the last n elements from the given slice.
// letters = ['a'..'z']
TakeLast(letters, 2)
// ['y', 'z']- Returns a slice containing the first elements satisfying the given predicate
// letters = ['a'..'z']
TakeWhile(letters, func(s rune) bool { return s < 'f' })
// ['a', 'b', 'c', 'd', 'e']- Returns a slice containing the last elements satisfying the given predicate
// letters = ['a'..'z']
TakeLastWhile(letters, func(s rune) bool { return s > 'w' })
// ['x', 'y', 'z']- Returns a slice of sliding windows, each of the given size, and with the given step
- Several last slices may have fewer elements than the given size
Windowed([]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}, 5, 1)
// [
// [1, 2, 3, 4, 5],
// [2, 3, 4, 5, 6],
// [3, 4, 5, 6, 7],
// [4, 5, 6, 7, 8],
// [5, 6, 7, 8, 9],
// [6, 7, 8, 9, 10],
// [7, 8, 9, 10],
// [8, 9, 10],
// [9, 10],
// [10]
// ]
Windowed([]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}, 5, 3)
// [
// [1, 2, 3, 4, 5],
// [4, 5, 6, 7, 8],
// [7, 8, 9, 10],
// [10]
// ]