lancet/docs/api/packages/maputil.md

# Maputil

maputil 包包括一些操作 map 的函数。

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## 源码:

-   [https://github.com/duke-git/lancet/blob/main/maputil/map.go](https://github.com/duke-git/lancet/blob/main/maputil/map.go)
-   [https://github.com/duke-git/lancet/blob/main/maputil/concurrentmap.go](https://github.com/duke-git/lancet/blob/main/maputil/concurrentmap.go)
-   [https://github.com/duke-git/lancet/blob/main/maputil/orderedmap.go](https://github.com/duke-git/lancet/blob/main/maputil/orderedmap.go)

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## 用法:

```go
import (
    "github.com/duke-git/lancet/v2/maputil"
)
```

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## 目录:

-   [MapTo](#MapTo)
-   [ForEach](#ForEach)
-   [Filter](#Filter)
-   [FilterByKeys](#FilterByKeys)
-   [FilterByValues](#FilterByValues)
-   [OmitBy](#OmitBy)
-   [OmitByKeys](#OmitByKeys)
-   [OmitByValues](#OmitByValues)
-   [Intersect](#Intersect)
-   [Keys](#Keys)
-   [Values](#Values)
-   [KeysBy](#KeysBy)
-   [ValuesBy](#ValuesBy)
-   [MapKeys](#MapKeys)
-   [MapValues](#MapValues)
-   [Entries](#Entries)
-   [FromEntries](#FromEntries)
-   [Transform](#Transform)
-   [Merge](#Merge)
-   [Minus](#Minus)
-   [IsDisjoint](#IsDisjoint)
-   [HasKey](#HasKey)
-   [MapToStruct](#MapToStruct)
-   [ToSortedSlicesDefault](#ToSortedSlicesDefault)
-   [ToSortedSlicesWithComparator](#ToSortedSlicesWithComparator)
-   [NewOrderedMap](#NewOrderedMap)
-   [OrderedMap_Set](#OrderedMap_Set)
-   [OrderedMap_Get](#OrderedMap_Get)
-   [OrderedMap_Front](#OrderedMap_Front)
-   [OrderedMap_Back](#OrderedMap_Back)
-   [OrderedMap_Delete](#OrderedMap_Delete)
-   [OrderedMap_Clear](#OrderedMap_Clear)
-   [OrderedMap_Len](#OrderedMap_Len)
-   [OrderedMap_Keys](#OrderedMap_Keys)
-   [OrderedMap_Values](#OrderedMap_Values)
-   [OrderedMap_Contains](#OrderedMap_Contains)
-   [OrderedMap_Range](#OrderedMap_Range)
-   [OrderedMap_Elements](#OrderedMap_Elements)
-   [OrderedMap_Iter](#OrderedMap_Iter)
-   [OrderedMap_ReverseIter](#OrderedMap_ReverseIter)
-   [OrderedMap_SortByKey](#OrderedMap_SortByKey)
-   [OrderedMap_MarshalJSON](#OrderedMap_MarshalJSON)
-   [OrderedMap_UnmarshalJSON](#OrderedMap_UnmarshalJSON)
-   [NewConcurrentMap](#NewConcurrentMap)
-   [ConcurrentMap_Get](#ConcurrentMap_Get)
-   [ConcurrentMap_Set](#ConcurrentMap_Set)
-   [ConcurrentMap_GetOrSet](#ConcurrentMap_GetOrSet)
-   [ConcurrentMap_Delete](#ConcurrentMap_Delete)
-   [ConcurrentMap_GetAndDelete](#ConcurrentMap_GetAndDelete)
-   [ConcurrentMap_Has](#ConcurrentMap_Has)
-   [ConcurrentMap_Range](#ConcurrentMap_Range)
-   [GetOrSet](#GetOrSet)
-   [SortByKey](#SortByKey)
-   [GetOrDefault](#GetOrDefault)
-   [FindValuesBy](#FindValuesBy)
-   [ToMarkdownTable](#ToMarkdownTable)

<div STYLE="page-break-after: always;"></div>

## API 文档:

### <span id="MapTo">MapTo</span>

<p>快速将map或者其他类型映射到结构体或者指定类型。</p>

<b>函数签名:</b>

```go
func MapTo(src any, dst any) error
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/4K7KBEPgS5M)</span></b>

```go
package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    type (
        Person struct {
            Name  string  `json:"name"`
            Age   int     `json:"age"`
            Phone string  `json:"phone"`
            Addr  Address `json:"address"`
        }

        Address struct {
            Street string `json:"street"`
            Number int    `json:"number"`
        }
    )

    personInfo := map[string]interface{}{
        "name":  "Nothin",
        "age":   28,
        "phone": "123456789",
        "address": map[string]interface{}{
            "street": "test",
            "number": 1,
        },
    }

    var p Person
    err := MapTo(personInfo, &p)

    fmt.Println(err)
    fmt.Println(p)

    // Output:
    // <nil>
    // {Nothin 28 123456789 {test 1}}
}
```

### <span id="ForEach">ForEach</span>

<p>对map中的每对key和value执行iteratee函数</p>

<b>函数签名:</b>

```go
func ForEach[K comparable, V any](m map[K]V, iteratee func(key K, value V))
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/OaThj6iNVXK)</span></b>

```go
package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    m := map[string]int{
        "a": 1,
        "b": 2,
        "c": 3,
        "d": 4,
    }

    var sum int

    maputil.ForEach(m, func(_ string, value int) {
        sum += value
    })

    fmt.Println(sum)

    // Output:
    // 10
}
```

### <span id="Filter">Filter</span>

<p>迭代map中的每对key和value, 返回符合predicate函数的key, value。</p>

<b>函数签名:</b>

```go
func Filter[K comparable, V any](m map[K]V, predicate func(key K, value V) bool) map[K]V
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/fSvF3wxuNG7)</span></b>

```go
package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    m := map[string]int{
        "a": 1,
        "b": 2,
        "c": 3,
        "d": 4,
        "e": 5,
    }
    isEven := func(_ string, value int) bool {
        return value%2 == 0
    }

    maputil.Filter(m, func(_ string, value int) {
        sum += value
    })

    result := Filter(m, isEven)

    fmt.Println(result)

    // Output:
    // map[b:2 d:4]
}
```

### <span id="FilterByKeys">FilterByKeys</span>

<p>迭代map, 返回一个新map，其key都是给定的key值。</p>

<b>函数签名:</b>

```go
func FilterByKeys[K comparable, V any](m map[K]V, keys []K) map[K]V
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/7ov6BJHbVqh)</span></b>

```go
package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    m := map[string]int{
        "a": 1,
        "b": 2,
        "c": 3,
        "d": 4,
        "e": 5,
    }

    result := maputil.FilterByKeys(m, []string{"a", "b"})

    fmt.Println(result)

    // Output:
    // map[a:1 b:2]
}
```

### <span id="FilterByValues">FilterByValues</span>

<p>迭代map, 返回一个新map，其value都是给定的value值。</p>

<b>函数签名:</b>

```go
func FilterByValues[K comparable, V comparable](m map[K]V, values []V) map[K]V
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/P3-9MdcXegR)</span></b>

```go
package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    m := map[string]int{
        "a": 1,
        "b": 2,
        "c": 3,
        "d": 4,
        "e": 5,
    }

    result := maputil.FilterByValues(m, []int{3, 4})

    fmt.Println(result)

    // Output:
    // map[c:3 d:4]
}
```

### <span id="OmitBy">OmitBy</span>

<p>Filter的反向操作, 迭代map中的每对key和value, 删除符合predicate函数的key, value, 返回新map。</p>

<b>函数签名:</b>

```go
func OmitBy[K comparable, V any](m map[K]V, predicate func(key K, value V) bool) map[K]V
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/YJM4Hj5hNwm)</span></b>

```go
package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    m := map[string]int{
        "a": 1,
        "b": 2,
        "c": 3,
        "d": 4,
        "e": 5,
    }
    isEven := func(_ string, value int) bool {
        return value%2 == 0
    }

    result := maputil.OmitBy(m, isEven)

    fmt.Println(result)

    // Output:
    // map[a:1 c:3 e:5]
}
```

### <span id="OmitByKeys">OmitByKeys</span>

<p>FilterByKeys的反向操作, 迭代map, 返回一个新map，其key不包括给定的key值。</p>

<b>函数签名:</b>

```go
func OmitByKeys[K comparable, V any](m map[K]V, keys []K) map[K]V
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/jXGrWDBfSRp)</span></b>

```go
package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    m := map[string]int{
        "a": 1,
        "b": 2,
        "c": 3,
        "d": 4,
        "e": 5,
    }

    result := maputil.OmitByKeys(m, []string{"a", "b"})

    fmt.Println(result)

    // Output:
    // map[c:3 d:4 e:5]
}
```

### <span id="OmitByValues">OmitByValues</span>

<p>FilterByValues的反向操作, 迭代map, 返回一个新map，其value不包括给定的value值。</p>

<b>函数签名:</b>

```go
func OmitByValues[K comparable, V comparable](m map[K]V, values []V) map[K]V
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/XB7Y10uw20_U)</span></b>

```go
package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    m := map[string]int{
        "a": 1,
        "b": 2,
        "c": 3,
        "d": 4,
        "e": 5,
    }

    result := maputil.OmitByValues(m, []int{4, 5})

    fmt.Println(result)

    // Output:
    // map[a:1 b:2 c:3]
}
```

### <span id="Intersect">Intersect</span>

<p>多个map的交集操作</p>

<b>函数签名:</b>

```go
func Intersect[K comparable, V any](maps ...map[K]V) map[K]V
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/Zld0oj3sjcC)</span></b>

```go
package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    m1 := map[string]int{
        "a": 1,
        "b": 2,
        "c": 3,
    }

    m2 := map[string]int{
        "a": 1,
        "b": 2,
        "c": 6,
        "d": 7,
    }

    m3 := map[string]int{
        "a": 1,
        "b": 9,
        "e": 9,
    }

    result1 := maputil.Intersect(m1)
    result2 := maputil.Intersect(m1, m2)
    result3 := maputil.Intersect(m1, m2, m3)

    fmt.Println(result1)
    fmt.Println(result2)
    fmt.Println(result3)

    // Output:
    // map[a:1 b:2 c:3]
    // map[a:1 b:2]
    // map[a:1]
}
```

### <span id="Keys">Keys</span>

<p>返回map中所有key的切片</p>

<b>函数签名:</b>

```go
func Keys[K comparable, V any](m map[K]V) []K
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/xNB5bTb97Wd)</span></b>

```go
package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    m := map[int]string{
        1: "a",
        2: "a",
        3: "b",
        4: "c",
        5: "d",
    }

    keys := maputil.Keys(m)
    sort.Ints(keys)

    fmt.Println(keys)

    // Output:
    // [1 2 3 4 5]
}
```

### <span id="Merge">Merge</span>

<p>合并多个maps, 相同的key会被后来的key覆盖</p>

<b>函数签名:</b>

```go
func Merge[K comparable, V any](maps ...map[K]V) map[K]V
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/H95LENF1uB-)</span></b>

```go
package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    m1 := map[int]string{
        1: "a",
        2: "b",
    }
    m2 := map[int]string{
        1: "1",
        3: "2",
    }

    result := maputil.Merge(m1, m2)

    fmt.Println(result)

    // Output:
    // map[1:c 2:b 3:d]
}
```

### <span id="Minus">Minus</span>

<p>返回一个map，其中的key存在于mapA，不存在于mapB.</p>

<b>函数签名:</b>

```go
func Minus[K comparable, V any](mapA, mapB map[K]V) map[K]V
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/3u5U9K7YZ9m)</span></b>

```go
package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    m1 := map[string]int{
        "a": 1,
        "b": 2,
        "c": 3,
    }

    m2 := map[string]int{
        "a": 11,
        "b": 22,
        "d": 33,
    }

    result := maputil.Minus(m1, m2)

    fmt.Println(result)

    // Output:
    // map[c:3]
}
```

### <span id="Values">Values</span>

<p>返回map中所有value的切片</p>

<b>函数签名:</b>

```go
func Values[K comparable, V any](m map[K]V) []V
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/CBKdUc5FTW6)</span></b>

```go
package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    m := map[int]string{
        1: "a",
        2: "a",
        3: "b",
        4: "c",
        5: "d",
    }

    values := maputil.Values(m)
    sort.Strings(values)

    // Output:
    // [a a b c d]
}
```

### <span id="KeysBy">KeysBy</span>

<p>创建一个切片，其元素是每个map的key调用mapper函数的结果。</p>

<b>函数签名:</b>

```go
func KeysBy[K comparable, V any, T any](m map[K]V, mapper func(item K) T) []T
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/hI371iB8Up8)</span></b>

```go
package main

import (
    "fmt"
    "sort"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    m := map[int]string{
        1: "a",
        2: "a",
        3: "b",
    }

    keys := maputil.KeysBy(m, func(n int) int {
        return n + 1
    })

    sort.Ints(keys)

    fmt.Println(keys)

    // Output:
    // [2 3 4]
}
```

### <span id="ValuesBy">ValuesBy</span>

<p>创建一个切片，其元素是每个map的value调用mapper函数的结果。</p>

<b>函数签名:</b>

```go
func ValuesBy[K comparable, V any, T any](m map[K]V, mapper func(item V) T) []T
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/sg9-oRidh8f)</span></b>

```go
package main

import (
    "fmt"
    "sort"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    m := map[int]string{
        1: "a",
        2: "b",
        3: "c",
    }
    values := maputil.ValuesBy(m, func(v string) string {
        switch v {
        case "a":
            return "a-1"
        case "b":
            return "b-2"
        case "c":
            return "c-3"
        default:
            return ""
        }
    })

    sort.Strings(values)

    fmt.Println(values)

    // Output:
    // [a-1 b-2 c-3]
}
```

### <span id="MapKeys">MapKeys</span>

<p>操作map的每个key，然后转为新的map。</p>

<b>函数签名:</b>

```go
func MapKeys[K comparable, V any, T comparable](m map[K]V, iteratee func(key K, value V) T) map[T]V
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/8scDxWeBDKd)</span></b>

```go
package main

import (
    "fmt"
    "strconv"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    m := map[int]string{
        1: "a",
        2: "b",
        3: "c",
    }

    result := maputil.MapKeys(m, func(k int, _ string) string {
        return strconv.Itoa(k)
    })

    fmt.Println(result)

    // Output:
    // map[1:a 2:b 3:c]
}
```

### <span id="MapValues">MapValues</span>

<p>操作map的每个value，然后转为新的map。</p>

<b>函数签名:</b>

```go
func MapValues[K comparable, V any, T any](m map[K]V, iteratee func(key K, value V) T) map[K]T
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/g92aY3fc7Iw)</span></b>

```go
package main

import (
    "fmt"
    "strconv"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    m := map[int]string{
        1: "a",
        2: "b",
        3: "c",
    }

    result := maputil.MapValues(m, func(k int, v string) string {
        return v + strconv.Itoa(k)
    })

    fmt.Println(result)

    // Output:
    // map[1:a1 2:b2 3:c3]
}
```

### <span id="Entry">Entry</span>

<p>将map转换为键/值对切片。</p>

<b>函数签名:</b>

```go
type Entry[K comparable, V any] struct {
    Key   K
    Value V
}
func Entries[K comparable, V any](m map[K]V) []Entry[K, V]
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/Ltb11LNcElY)</span></b>

```go
package main

import (
    "fmt"
    "sort"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    m := map[string]int{
        "a": 1,
        "b": 2,
        "c": 3,
    }

    result := maputil.Entries(m)

    sort.Slice(result, func(i, j int) bool {
        return result[i].Value < result[j].Value
    })

    fmt.Println(result)

    // Output:
    // [{a 1} {b 2} {c 3}]
}
```

### <span id="FromEntries">FromEntries</span>

<p>基于键/值对的切片创建map。</p>

<b>函数签名:</b>

```go
type Entry[K comparable, V any] struct {
    Key   K
    Value V
}
func FromEntries[K comparable, V any](entries []Entry[K, V]) map[K]V
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/C8L4ul9TVwf)</span></b>

```go
package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    result := maputil.FromEntries([]Entry[string, int]{
        {Key: "a", Value: 1},
        {Key: "b", Value: 2},
        {Key: "c", Value: 3},
    })

    fmt.Println(result)

    // Output:
    // map[a:1 b:2 c:3]
}
```

### <span id="Transform">Transform</span>

<p>将map转换为其他类型的map。</p>

<b>函数签名:</b>

```go
func Transform[K1 comparable, V1 any, K2 comparable, V2 any](m map[K1]V1, iteratee func(key K1, value V1) (K2, V2)) map[K2]V2
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/P6ovfToM3zj)</span></b>

```go
package main

import (
    "fmt"
    "strconv"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    m := map[string]int{
        "a": 1,
        "b": 2,
        "c": 3,
    }

    result := Transform(m, func(k string, v int) (string, string) {
        return k, strconv.Itoa(v)
    })

    fmt.Println(result)

    // Output:
    // map[a:1 b:2 c:3]
}
```

### <span id="IsDisjoint">IsDisjoint</span>

<p>验证两个map是否具有不同的key</p>

<b>函数签名:</b>

```go
func IsDisjoint[K comparable, V any](mapA, mapB map[K]V) bool
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/N9qgYg_Ho6f)</span></b>

```go
package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    m1 := map[string]int{
        "a": 1,
        "b": 2,
        "c": 3,
    }

    m2 := map[string]int{
        "d": 22,
    }

    m3 := map[string]int{
        "a": 22,
    }

    result1 := maputil.IsDisjoint(m1, m2)
    result2 := maputil.IsDisjoint(m1, m3)

    fmt.Println(result1)
    fmt.Println(result2)

    // Output:
    // true
    // false
}
```

### <span id="HasKey">HasKey</span>

<p>检查map是否包含某个key。用于代替以下样板代码:</p>

<b>函数签名:</b>

```go
func HasKey[K comparable, V any](m map[K]V, key K) bool
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/isZZHOsDhFc)</span></b>

```go
package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    m := map[string]int{
        "a": 1,
        "b": 2,
    }

    result1 := maputil.HasKey(m, "a")
    result2 := maputil.HasKey(m, "c")

    fmt.Println(result1)
    fmt.Println(result2)

    // Output:
    // true
    // false
}
```

### <span id="MapToStruct">MapToStruct</span>

<p>将map转成struct。</p>

<b>函数签名:</b>

```go
func MapToStruct(m map[string]any, structObj any) error
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/7wYyVfX38Dp)</span></b>

```go
package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    personReqMap := map[string]any{
        "name":     "Nothin",
        "max_age":  35,
        "page":     1,
        "pageSize": 10,
    }

    type PersonReq struct {
        Name     string `json:"name"`
        MaxAge   int    `json:"max_age"`
        Page     int    `json:"page"`
        PageSize int    `json:"pageSize"`
    }
    var personReq PersonReq
    _ = maputil.MapToStruct(personReqMap, &personReq)
    fmt.Println(personReq)

    // Output:
    // {Nothin 35 1 10}
}
```

### <span id="ToSortedSlicesDefault">ToSortedSlicesDefault</span>

<p>将map的key和value转化成两个根据key的值从小到大排序的切片，value切片中元素的位置与key对应。</p>

<b>函数签名:</b>

```go
func ToSortedSlicesDefault[K constraints.Ordered, V any](m map[K]V) ([]K, []V)
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/43gEM2po-qy)</span></b>

```go
package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    m := map[int]string{
        1: "a",
        3: "c",
        2: "b",
    }

    keys, values := ToSortedSlicesDefault(m)

    fmt.Println(keys)
    fmt.Println(values)

    // Output:
    // [1 2 3]
    // [a b c]
}
```

### <span id="ToSortedSlicesWithComparator">ToSortedSlicesWithComparator</span>

<p>将map的key和value转化成两个使用比较器函数根据key的值自定义排序规则的切片，value切片中元素的位置与key对应。</p>

<b>函数签名:</b>

```go
func ToSortedSlicesWithComparator[K comparable, V any](m map[K]V, comparator func(a, b K) bool) ([]K, []V)
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/0nlPo6YLdt3)</span></b>

```go
package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    m1 := map[time.Time]string{
        time.Date(2024, 3, 31, 0, 0, 0, 0, time.UTC): "today",
        time.Date(2024, 3, 30, 0, 0, 0, 0, time.UTC): "yesterday",
        time.Date(2024, 4, 1, 0, 0, 0, 0, time.UTC):  "tomorrow",
    }

    keys1, values1 := maputil.ToSortedSlicesWithComparator(m1, func(a, b time.Time) bool {
        return a.Before(b)
    })

    m2 := map[int]string{
        1: "a",
        3: "c",
        2: "b",
    }
    keys2, values2 := maputil.ToSortedSlicesWithComparator(m2, func(a, b int) bool {
        return a > b
    })

    fmt.Println(keys2)
    fmt.Println(values2)

    fmt.Println(keys1)
    fmt.Println(values1)

    // Output:
    // [3 2 1]
    // [c b a]
    // [2024-03-30 00:00:00 +0000 UTC 2024-03-31 00:00:00 +0000 UTC 2024-04-01 00:00:00 +0000 UTC]
    // [yesterday today tomorrow]
}
```

### <span id="NewOrderedMap">NewOrderedMap</span>

<p>创建有序映射。有序映射是键值对的集合，其中键是唯一的，并且保留键插入的顺序。</p>

<b>函数签名:</b>

```go
func NewOrderedMap[K comparable, V any]() *OrderedMap[K, V]
```

<b>示例:<span style="float:right;display:inline-block;">[运行]()</span></b>

```go
package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    om := maputil.NewOrderedMap[string, int]()

    om.Set("a", 1)
    om.Set("b", 2)
    om.Set("c", 3)

    val1, ok := om.Get("a")
    fmt.Println(val1, ok)

    val2, ok := om.Get("d")
    fmt.Println(val2, ok)

    // Output:
    // 1 true
    // 0 false
}
```

### <span id="OrderedMap_Set">OrderedMap_Set</span>

<p>设置给定的键值对。</p>

<b>函数签名:</b>

```go
func (om *OrderedMap[K, V]) Set(key K, value V)
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/Y4ZJ_oOc1FU)</span></b>

```go
package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    om := maputil.NewOrderedMap[string, int]()

    om.Set("a", 1)
    om.Set("b", 2)
    om.Set("c", 3)

    val1, ok := om.Get("a")
    fmt.Println(val1, ok)

    val2, ok := om.Get("d")
    fmt.Println(val2, ok)

    // Output:
    // 1 true
    // 0 false
}
```

### <span id="OrderedMap_Get">OrderedMap_Get</span>

<p>返回给定键的值。</p>

<b>函数签名:</b>

```go
func (om *OrderedMap[K, V]) Get(key K) (V, bool)
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/Y4ZJ_oOc1FU)</span></b>

```go
package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    om := maputil.NewOrderedMap[string, int]()

    om.Set("a", 1)
    om.Set("b", 2)
    om.Set("c", 3)

    val1, ok := om.Get("a")
    fmt.Println(val1, ok)

    val2, ok := om.Get("d")
    fmt.Println(val2, ok)

    // Output:
    // 1 true
    // 0 false
}
```

### <span id="OrderedMap_Delete">OrderedMap_Delete</span>

<p>删除给定键的键值对。</p>

<b>函数签名:</b>

```go
func (om *OrderedMap[K, V]) Delete(key K)
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/5bIi4yaZ3K-)</span></b>

```go
package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    om := maputil.NewOrderedMap[string, int]()

    om.Set("a", 1)
    om.Set("b", 2)
    om.Set("c", 3)

    om.Delete("b")

    fmt.Println(om.Keys())

    // Output:
    // [a c]
}
```

### <span id="OrderedMap_Clear">OrderedMap_Clear</span>

<p>清空map数据。</p>

<b>函数签名:</b>

```go
func (om *OrderedMap[K, V]) Clear()
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/8LwoJyEfuFr)</span></b>

```go
package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    om := maputil.NewOrderedMap[string, int]()

    om.Set("a", 1)
    om.Set("b", 2)
    om.Set("c", 3)

    om.Clear()

    fmt.Println(om.Keys())

    // Output:
    // []
}
```

### <span id="OrderedMap_Front">OrderedMap_Front</span>

<p>返回第一个键值对。</p>

<b>函数签名:</b>

```go
func (om *OrderedMap[K, V]) Front() (struct {
    Key   K
    Value V
}, bool)
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/ty57XSimpoe)</span></b>

```go
package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    om := maputil.NewOrderedMap[string, int]()

    om.Set("a", 1)
    om.Set("b", 2)
    om.Set("c", 3)

    frontElement, ok := om.Front()
    fmt.Println(frontElement)
    fmt.Println(ok)

    // Output:
    // {a 1}
    // true
}
```

### <span id="OrderedMap_Back">OrderedMap_Back</span>

<p>返回最后一个键值对。</p>

<b>函数签名:</b>

```go
func (om *OrderedMap[K, V]) Back() (struct {
    Key   K
    Value V
}, bool)
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/rQMjp1yQmpa)</span></b>

```go
package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    om := maputil.NewOrderedMap[string, int]()

    om.Set("a", 1)
    om.Set("b", 2)
    om.Set("c", 3)

    backElement, ok := om.Back()
    fmt.Println(backElement)
    fmt.Println(ok)

    // Output:
    // {c 3}
    // true
}
```

### <span id="OrderedMap_Range">OrderedMap_Range</span>

<p>为每个键值对调用给定的函数。</p>

<b>函数签名:</b>

```go
func (om *OrderedMap[K, V]) Range(iteratee func(key K, value V) bool)
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/U-KpORhc7LZ)</span></b>

```go
package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    om := maputil.NewOrderedMap[string, int]()

    om.Set("a", 1)
    om.Set("b", 2)
    om.Set("c", 3)

    om.Range(func(key string, value int) bool {
        fmt.Println(key, value)
        return true
    })

    // Output:
    // a 1
    // b 2
    // c 3
}
```

### <span id="OrderedMap_Keys">OrderedMap_Keys</span>

<p>按顺序返回键的切片。</p>

<b>函数签名:</b>

```go
func (om *OrderedMap[K, V]) Keys() []K
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/Vv_y9ExKclA)</span></b>

```go
package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    om := maputil.NewOrderedMap[string, int]()

    om.Set("a", 1)
    om.Set("b", 2)
    om.Set("c", 3)

    keys := om.Keys()

    fmt.Println(keys)

    // Output:
    // [a b c]
}
```

### <span id="OrderedMap_Values">OrderedMap_Values</span>

<p>按顺序返回值的切片。</p>

<b>函数签名:</b>

```go
func (om *OrderedMap[K, V]) Values() []V
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/TWj5n1-PUfx)</span></b>

```go
package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    om := maputil.NewOrderedMap[string, int]()

    om.Set("a", 1)
    om.Set("b", 2)
    om.Set("c", 3)

    values := om.Values()

    fmt.Println(values)

    // Output:
    // [1 2 3]
}
```

### <span id="OrderedMap_Elements">OrderedMap_Elements</span>

<p>按顺序返回键值对。</p>

<b>函数签名:</b>

```go
func (om *OrderedMap[K, V]) Elements() []struct
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/4BHG4kKz6bB)</span></b>

```go
package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    om := maputil.NewOrderedMap[string, int]()

    om.Set("a", 1)
    om.Set("b", 2)
    om.Set("c", 3)

    elements := om.Elements()

    fmt.Println(elements)

    // Output:
    // [{a 1} {b 2} {c 3}]
}
```

### <span id="OrderedMap_Len">OrderedMap_Len</span>

<p>返回键值对的数量。</p>

<b>函数签名:</b>

```go
func (om *OrderedMap[K, V]) Len() int
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/cLe6z2VX5N-)</span></b>

```go
package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    om := maputil.NewOrderedMap[string, int]()

    om.Set("a", 1)
    om.Set("b", 2)
    om.Set("c", 3)

    om.Len()

    fmt.Println(om.Len())

    // Output:
    // 3
}
```

### <span id="OrderedMap_Contains">OrderedMap_Contains</span>

<p>如果给定的键存在则返回true。</p>

<b>函数签名:</b>

```go
func (om *OrderedMap[K, V]) Contains(key K) bool
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/QuwqqnzwDNX)</span></b>

```go
package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    om := maputil.NewOrderedMap[string, int]()

    om.Set("a", 1)
    om.Set("b", 2)
    om.Set("c", 3)

    result1 := om.Contains("a")
    result2 := om.Contains("d")

    fmt.Println(result1)
    fmt.Println(result2)

    // Output:
    // true
    // false
}
```

### <span id="OrderedMap_Iter">OrderedMap_Iter</span>

<p>返回按顺序产生键值对的通道。</p>

<b>函数签名:</b>

```go
func (om *OrderedMap[K, V]) Iter() <-chan struct {
    Key   K
    Value V
}
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/tlq2tdvicPt)</span></b>

```go
package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    om := maputil.NewOrderedMap[string, int]()

    om.Set("a", 1)
    om.Set("b", 2)
    om.Set("c", 3)

    for elem := range om.Iter() {
        fmt.Println(elem)
    }

    // Output:
    // {a 1}
    // {b 2}
    // {c 3}
}
```

### <span id="OrderedMap_ReverseIter">OrderedMap_ReverseIter</span>

<p>返回以相反顺序产生键值对的通道。</p>

<b>函数签名:</b>

```go
func (om *OrderedMap[K, V]) ReverseIter() <-chan struct {
    Key   K
    Value V
}
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/8Q0ssg6hZzO)</span></b>

```go
package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    om := maputil.NewOrderedMap[string, int]()

    om.Set("a", 1)
    om.Set("b", 2)
    om.Set("c", 3)

    for elem := range om.ReverseIter() {
        fmt.Println(elem)
    }

    // Output:
    // {c 3}
    // {b 2}
    // {a 1}
}
```

### <span id="OrderedMap_SortByKey">OrderedMap_SortByKey</span>

<p>使用传入的比较函数排序map key。</p>

<b>函数签名:</b>

```go
func (om *OrderedMap[K, V]) SortByKey(less func(a, b K) bool)
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/N7hjD_alZPq)</span></b>

```go
package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    om := maputil.NewOrderedMap[int, string]()

    om.Set(3, "c")
    om.Set(1, "a")
    om.Set(4, "d")
    om.Set(2, "b")

    om.SortByKey(func(a, b int) bool {
        return a < b
    })

    fmt.Println(om.Elements())

    // Output:
    // [{1 a} {2 b} {3 c} {4 d}]
}
```

### <span id="OrderedMap_MarshalJSON">OrderedMap_MarshalJSON</span>

<p>实现json.Marshaler接口。</p>

<b>函数签名:</b>

```go
func (om *OrderedMap[K, V]) MarshalJSON() ([]byte, error)
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/C-wAwydIAC7)</span></b>

```go
package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    om := maputil.NewOrderedMap[int, string]()

    om.Set(3, "c")
    om.Set(1, "a")
    om.Set(4, "d")
    om.Set(2, "b")

    b, _ := om.MarshalJSON()

    fmt.Println(string(b))

    // Output:
    // {"a":1,"b":2,"c":3}
}
```

### <span id="OrderedMap_UnmarshalJSON">OrderedMap_UnmarshalJSON</span>

<p>实现json.Unmarshaler接口。</p>

<b>函数签名:</b>

```go
func (om *OrderedMap[K, V]) UnmarshalJSON(data []byte) error
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/8C3MvJ3-mut)</span></b>

```go
package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    om := maputil.NewOrderedMap[string, int]()

    data := []byte(`{"a":1,"b":2,"c":3}`)

    om.UnmarshalJSON(data)

    fmt.Println(om.Elements())

    // Output:
    // [{a 1} {b 2} {c 3}]
}
```

### <span id="NewConcurrentMap">NewConcurrentMap</span>

<p>ConcurrentMap协程安全的map结构。</p>

<b>函数签名:</b>

```go
// NewConcurrentMap create a ConcurrentMap with specific shard count.
func NewConcurrentMap[K comparable, V any](shardCount int) *ConcurrentMap[K, V]
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/3PenTPETJT0)</span></b>

```go
package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    // create a ConcurrentMap whose key type is string, value type is int
    cm := maputil.NewConcurrentMap[string, int](100)
}
```

### <span id="ConcurrentMap_Set">ConcurrentMap_Set</span>

<p>在map中设置key和value。</p>

<b>函数签名:</b>

```go
func (cm *ConcurrentMap[K, V]) Set(key K, value V)
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/3PenTPETJT0)</span></b>

```go
package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    cm := maputil.NewConcurrentMap[string, int](100)

    var wg1 sync.WaitGroup
    wg1.Add(5)

    for i := 0; i < 5; i++ {
        go func(n int) {
            cm.Set(fmt.Sprintf("%d", n), n)
            wg1.Done()
        }(i)
    }
    wg1.Wait()

    var wg2 sync.WaitGroup
    wg2.Add(5)
    for j := 0; j < 5; j++ {
        go func(n int) {
            val, ok := cm.Get(fmt.Sprintf("%d", n))
            fmt.Println(val, ok)
            wg2.Done()
        }(j)
    }
    wg2.Wait()

    // output: (order may change)
    // 1 true
    // 3 true
    // 2 true
    // 0 true
    // 4 true
}
```

### <span id="ConcurrentMap_Get">ConcurrentMap_Get</span>

<p>根据key获取value, 如果不存在key,返回零值。</p>

<b>函数签名:</b>

```go
func (cm *ConcurrentMap[K, V]) Get(key K) (V, bool)
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/3PenTPETJT0)</span></b>

```go
package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    cm := maputil.NewConcurrentMap[string, int](100)

    var wg1 sync.WaitGroup
    wg1.Add(5)

    for i := 0; i < 5; i++ {
        go func(n int) {
            cm.Set(fmt.Sprintf("%d", n), n)
            wg1.Done()
        }(i)
    }
    wg1.Wait()

    var wg2 sync.WaitGroup
    wg2.Add(5)
    for j := 0; j < 5; j++ {
        go func(n int) {
            val, ok := cm.Get(fmt.Sprintf("%d", n))
            fmt.Println(val, ok)
            wg2.Done()
        }(j)
    }
    wg2.Wait()

    // output: (order may change)
    // 1 true
    // 3 true
    // 2 true
    // 0 true
    // 4 true
}
```

### <span id="ConcurrentMap_GetOrSet">ConcurrentMap_GetOrSet</span>

<p>返回键的现有值（如果存在），否则，设置key并返回给定值。</p>

<b>函数签名:</b>

```go
func (cm *ConcurrentMap[K, V]) GetOrSet(key K, value V) (actual V, ok bool)
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/aDcDApOK01a)</span></b>

```go
package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    cm := maputil.NewConcurrentMap[string, int](100)

    var wg sync.WaitGroup
    wg.Add(5)

    for i := 0; i < 5; i++ {
        go func(n int) {
            val, ok := cm.GetOrSet(fmt.Sprintf("%d", n), n)
            fmt.Println(val, ok)
            wg.Done()
        }(i)
    }
    wg.Wait()

    // output: (order may change)
    // 1 false
    // 3 false
    // 2 false
    // 0 false
    // 4 false
}
```

### <span id="ConcurrentMap_Delete">ConcurrentMap_Delete</span>

<p>删除key。</p>

<b>函数签名:</b>

```go
func (cm *ConcurrentMap[K, V]) Delete(key K)
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/uTIJZYhpVMS)</span></b>

```go
package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    cm := maputil.NewConcurrentMap[string, int](100)

    var wg1 sync.WaitGroup
    wg1.Add(5)

    for i := 0; i < 5; i++ {
        go func(n int) {
            cm.Set(fmt.Sprintf("%d", n), n)
            wg1.Done()
        }(i)
    }
    wg1.Wait()

    var wg2 sync.WaitGroup
    wg2.Add(5)
    for j := 0; j < 5; j++ {
        go func(n int) {
            cm.Delete(fmt.Sprintf("%d", n))
            wg2.Done()
        }(i)
    }
    wg2.Wait()
}
```

### <span id="ConcurrentMap_GetAndDelete">ConcurrentMap_GetAndDelete</span>

<p>获取key，然后删除。</p>

<b>函数签名:</b>

```go
func (cm *ConcurrentMap[K, V]) GetAndDelete(key K) (actual V, ok bool)
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/ZyxeIXSZUiM)</span></b>

```go
package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    cm := maputil.NewConcurrentMap[string, int](100)

    var wg1 sync.WaitGroup
    wg1.Add(5)

    for i := 0; i < 5; i++ {
        go func(n int) {
            cm.Set(fmt.Sprintf("%d", n), n)
            wg1.Done()
        }(i)
    }
    wg1.Wait()

    var wg2 sync.WaitGroup
    wg2.Add(5)
    for j := 0; j < 5; j++ {
        go func(n int) {
            val, ok := cm.GetAndDelete(fmt.Sprintf("%d", n))
            fmt.Println(val, ok) //n, true

            _, ok = cm.Get(fmt.Sprintf("%d", n))
            fmt.Println(val, ok) //false

            wg2.Done()
        }(j)
    }
    wg2.Wait()
}
```

### <span id="ConcurrentMap_Has">ConcurrentMap_Has</span>

<p>验证是否包含key。</p>

<b>函数签名:</b>

```go
func (cm *ConcurrentMap[K, V]) Has(key K) bool
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/C8L4ul9TVwf)</span></b>

```go
package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    cm := maputil.NewConcurrentMap[string, int](100)

    var wg1 sync.WaitGroup
    wg1.Add(5)
    for i := 0; i < 5; i++ {
        go func(n int) {
            cm.Set(fmt.Sprintf("%d", n), n)
            wg1.Done()
        }(i)
    }
    wg1.Wait()

    var wg2 sync.WaitGroup
    wg2.Add(5)

    for j := 0; j < 5; j++ {
        go func(n int) {
            ok := cm.Has(fmt.Sprintf("%d", n))
            fmt.Println(ok) // true

            wg2.Done()
        }(j)
    }
    wg2.Wait()
}
```

### <span id="ConcurrentMap_Range">ConcurrentMap_Range</span>

<p>为map中每个键和值顺序调用迭代器。 如果iterator返回false，则停止迭代。</p>

<b>函数签名:</b>

```go
func (cm *ConcurrentMap[K, V]) Range(iterator func(key K, value V) bool)
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/iqcy7P8P0Pr)</span></b>

```go
package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    cm := maputil.NewConcurrentMap[string, int](100)

    var wg1 sync.WaitGroup
    wg1.Add(5)

    for i := 0; i < 5; i++ {
        go func(n int) {
            cm.Set(fmt.Sprintf("%d", n), n)
            wg1.Done()
        }(i)
    }
    wg1.Wait()


    cm.Range(func(key string, value int) bool {
        fmt.Println(value)
        return true
    })
}
```

### <span id="GetOrSet">GetOrSet</span>

<p>返回给定键的值，如果不存在则设置该值。</p>

<b>函数签名:</b>

```go
func GetOrSet[K comparable, V any](m map[K]V, key K, value V) V
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/IVQwO1OkEJC)</span></b>

```go
package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    m := map[int]string{
        1: "a",
    }

    result1 := maputil.GetOrSet(m, 1, "1")
    result2 := maputil.GetOrSet(m, 2, "b")

    fmt.Println(result1)
    fmt.Println(result2)

    // Output:
    // a
    // b
}
```

### <span id="SortByKey">SortByKey</span>

<p>对传入的map根据key进行排序，返回排序后的map。</p>

<b>函数签名:</b>

```go
func SortByKey[K constraints.Ordered, V any](m map[K]V) (sortedKeysMap map[K]V)
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/PVdmBSnm6P_W)</span></b>

```go
package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    m := map[int]string{
        3: "c",
        1: "a",
        4: "d",
        2: "b",
    }

    result := maputil.SortByKey(m, func(a, b int) bool {
        return a < b
    })

    fmt.Println(result)

    // Output:
    // map[1:a 2:b 3:c 4:d]
}
```

### <span id="GetOrDefault">GetOrDefault</span>

<p>返回给定键的值，如果键不存在，则返回默认值。</p>

<b>函数签名:</b>

```go
func GetOrDefault[K comparable, V any](m map[K]V, key K, defaultValue V) V
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/99QjSYSBdiM)</span></b>

```go
package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    m := map[int]string{
        3: "c",
        1: "a",
        4: "d",
        2: "b",
    }

    result1 := maputil.GetOrDefault(m, 1, "default")
    result2 := maputil.GetOrDefault(m, 6, "default")

    fmt.Println(result1)
    fmt.Println(result2)

    // Output:
    // a
    // default
}
```

### <span id="FindValuesBy">FindValuesBy</span>

<p>返回一个切片，包含满足给定谓词判断函数的map中的值。</p>

<b>函数签名:</b>

```go
func FindValuesBy[K comparable, V any](m map[K]V, predicate func(key K, value V) bool) []V
```

<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/bvNwNBZDm6v)</span></b>

```go
package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    m := map[int]string{
        1: "a",
        2: "b",
        3: "c",
        4: "d",
    }

    result := maputil.FindValuesBy(m, func(k int, v string) bool {
        return k%2 == 0
    })

    fmt.Println(result)

    // Output:
    // [b d]
}
```

### <span id="ToMarkdownTable">ToMarkdownTable</span>

<p>将一个 map 切片数据转换为 Markdown 表格字符串。支持自定义表头显示名称和列的显示顺序。</p>

<b>函数签名:</b>

```go
编辑
func ToMarkdownTable(data []map[string]interface{}, headerMap map[string]string, columnOrder []string) string
```
<b>示例:<span style="float:right;display:inline-block;">[运行]()</span></b>


```go
package main

import (
    "fmt"
    "github.com/duke-git/lancet/v2/maputil"
)

func main() {
    // 基本用法：自动从数据中提取列名作为表头
    data := []map[string]interface{}{
        {"name": "Alice", "age": 25, "salary": 50000},
        {"name": "Bob", "age": 30, "salary": 60000},
    }

    result := maputil.ToMarkdownTable(data, nil, nil)
    fmt.Println(result)

    // 输出:
    // |name|age|salary|
    // |---|---|---|
    // |Alice|25|50000|
    // |Bob|30|60000|

    // 自定义表头显示名称
    headerMap := map[string]string{
        "name":   "姓名",
        "age":    "年龄",
        "salary": "薪资",
    }
    result = maputil.ToMarkdownTable(data, headerMap, nil)
    fmt.Println(result)

    // 输出:
    // |姓名|年龄|薪资|
    // |---|---|---|
    // |Alice|25|50000|
    // |Bob|30|60000|

    // 自定义列顺序
    columnOrder := []string{"salary", "name"}
    result = maputil.ToMarkdownTable(data, nil, columnOrder)
    fmt.Println(result)

    // 输出:
    // |salary|name|
    // |---|---|
    // |50000|Alice|
    // |60000|Bob|
}
```