From 754bbf7a25a8dda49b5d08ef0d0443bbf5af0e36 Mon Sep 17 00:00:00 2001 From: Craig Jennings Date: Sun, 7 Apr 2024 13:41:34 -0500 Subject: new repository --- devdocs/go/maps%2Findex.html | 126 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 126 insertions(+) create mode 100644 devdocs/go/maps%2Findex.html (limited to 'devdocs/go/maps%2Findex.html') diff --git a/devdocs/go/maps%2Findex.html b/devdocs/go/maps%2Findex.html new file mode 100644 index 00000000..3d751a7d --- /dev/null +++ b/devdocs/go/maps%2Findex.html @@ -0,0 +1,126 @@ +

Package maps

Overview

Package maps defines various functions useful with maps of any type.

Index

Examples

Clone
Copy
DeleteFunc
Equal
EqualFunc

Package files

maps.go

func Clone 

func Clone[M ~map[K]V, K comparable, V any](m M) M

Clone returns a copy of m. This is a shallow clone: the new keys and values are set using ordinary assignment.

Example +

Code:

m1 := map[string]int{
+    "key": 1,
+}
+m2 := maps.Clone(m1)
+m2["key"] = 100
+fmt.Println(m1["key"])
+fmt.Println(m2["key"])
+
+m3 := map[string][]int{
+    "key": {1, 2, 3},
+}
+m4 := maps.Clone(m3)
+fmt.Println(m4["key"][0])
+m4["key"][0] = 100
+fmt.Println(m3["key"][0])
+fmt.Println(m4["key"][0])
+
+

Output:

1
+100
+1
+100
+100
+

func Copy 

func Copy[M1 ~map[K]V, M2 ~map[K]V, K comparable, V any](dst M1, src M2)

Copy copies all key/value pairs in src adding them to dst. When a key in src is already present in dst, the value in dst will be overwritten by the value associated with the key in src.

Example +

Code:

m1 := map[string]int{
+    "one": 1,
+    "two": 2,
+}
+m2 := map[string]int{
+    "one": 10,
+}
+
+maps.Copy(m2, m1)
+fmt.Println("m2 is:", m2)
+
+m2["one"] = 100
+fmt.Println("m1 is:", m1)
+fmt.Println("m2 is:", m2)
+
+m3 := map[string][]int{
+    "one": {1, 2, 3},
+    "two": {4, 5, 6},
+}
+m4 := map[string][]int{
+    "one": {7, 8, 9},
+}
+
+maps.Copy(m4, m3)
+fmt.Println("m4 is:", m4)
+
+m4["one"][0] = 100
+fmt.Println("m3 is:", m3)
+fmt.Println("m4 is:", m4)
+
+

Output:

m2 is: map[one:1 two:2]
+m1 is: map[one:1 two:2]
+m2 is: map[one:100 two:2]
+m4 is: map[one:[1 2 3] two:[4 5 6]]
+m3 is: map[one:[100 2 3] two:[4 5 6]]
+m4 is: map[one:[100 2 3] two:[4 5 6]]
+

func DeleteFunc 

func DeleteFunc[M ~map[K]V, K comparable, V any](m M, del func(K, V) bool)

DeleteFunc deletes any key/value pairs from m for which del returns true.

Example +

Code:

m := map[string]int{
+    "one":   1,
+    "two":   2,
+    "three": 3,
+    "four":  4,
+}
+maps.DeleteFunc(m, func(k string, v int) bool {
+    return v%2 != 0 // delete odd values
+})
+fmt.Println(m)
+

Output:

map[four:4 two:2]
+

func Equal 

func Equal[M1, M2 ~map[K]V, K, V comparable](m1 M1, m2 M2) bool

Equal reports whether two maps contain the same key/value pairs. Values are compared using ==.

Example +

Code:

m1 := map[int]string{
+    1:    "one",
+    10:   "Ten",
+    1000: "THOUSAND",
+}
+m2 := map[int]string{
+    1:    "one",
+    10:   "Ten",
+    1000: "THOUSAND",
+}
+m3 := map[int]string{
+    1:    "one",
+    10:   "ten",
+    1000: "thousand",
+}
+
+fmt.Println(maps.Equal(m1, m2))
+fmt.Println(maps.Equal(m1, m3))
+

Output:

true
+false
+

func EqualFunc 

func EqualFunc[M1 ~map[K]V1, M2 ~map[K]V2, K comparable, V1, V2 any](m1 M1, m2 M2, eq func(V1, V2) bool) bool

EqualFunc is like Equal, but compares values using eq. Keys are still compared with ==.

Example +

Code:

m1 := map[int]string{
+    1:    "one",
+    10:   "Ten",
+    1000: "THOUSAND",
+}
+m2 := map[int][]byte{
+    1:    []byte("One"),
+    10:   []byte("Ten"),
+    1000: []byte("Thousand"),
+}
+eq := maps.EqualFunc(m1, m2, func(v1 string, v2 []byte) bool {
+    return strings.ToLower(v1) == strings.ToLower(string(v2))
+})
+fmt.Println(eq)
+

Output:

true
+
+

+ © Google, Inc.
Licensed under the Creative Commons Attribution License 3.0.
+ http://golang.org/pkg/maps/ +

+
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