Go Language Basics Summary

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second//The following code can not be used directly, the go language all declared variables to use, otherwise will be error//The following code is just the Go language basic summary, including from the variable declaration to switch branch package mainimport ("FMT")// DECLARE constant const (i = 0s string = "Test" Start string = "Go language start"//The first uppercase variable is public (to be verified))//Declare a set of global variables Var (k Ints2 St ringflag bool)//enum type iota keyword, default is 0, each autogrow 1const (p1 = Iota//p1=0p2 = Iota//p2=1p3//p3=2p4//p4=3) func testm          AP () {VAR MP map[string]int//declares a MAPMP2: = Make (Map[string]int)//map Another way of declaring mp2["one"] = 1mp2["two"] = 2 Assigns a FMT to map. Println (mp2["both"])//The value corresponding to the key is printed out//map is unordered, each printing is different, can only be obtained by key. Built-in method Len returns the number of keys for the map mp2["one"] = 10//Change the value of one to 10m3: = mp2m3["one"] = 4//At this time mp2["one" of MP2) becomes 4d Elete (MP2, "one")//delete key for one element rating: = map[string]int{"1": 2, "2": 3}//Initialize a dictionary}//goto statement func test Goto () {i: = 0Here://Declare a jump tag fmt. PRINTLN (i) if I < {I++goto here//jump to label}}//for statement func testfor () {var s [10]intfor J: = 0; J < Len (s); + J {S[j] = J//Array responsible for}for J: = 0; J < Len (s); J + + {FMT. PrIntln (S[j])//print each value of an array}//for+if statement for I: = 0; I < 100; i++ {if i%3 = = 0 && i%5! = 0 {fmt. Println ("Fizz")} else if i%5 = = 0 && i%3! = 0 {fmt. Println ("Bizz")} else if i%15 = = 0 {fmt. Println ("Fizzbizz")} else {fmt. Println (i)}}//prints a pyramid-shaped afor I: = 1; I <= 100; i++ {for J: = 1; J <= I; j + + {FMT. Printf ("%s", "A")}fmt. PRINTLN ()}}//traversal Mapfunc Eachmap () {mp2: = Make (Map[string]int)//map Another way of declaring mp2["one"] = 1mp2["two"] = 2for k, V: = range m P2 {fmt. Println ("Key:", K) fmt. Println ("Val:", v)}//only outputs the value of map for _, V: = range MP2 {fmt. Println ("Val:", v)}}//switch statement func Testswitch () {index: = 4switch Index {case 4:fmt. Println ("Hello 4") Fallthrough//enforces the following statement in case 5:fmt. Println ("Hello 5") default:fmt. PRINTLN ("Continue test")}}//uppercase method is public method, Func Test () {var arr [10]int//Declares a shape array of length 10 arr[0] = 10/assignment Arr[1] = 20arr2: = [3]in T{1, 2, 3}//Declare a shaped array of length 3 and assign a value of arr3: = [...] Int{2, 3, 4}//dynamically declares an array doublearray: = [2][2]int{[2]int{1, 2}, [2]int{3, 4}}                                     Declares a two-dimensional array easydouble: = [2][2]int{{1, 2}, {2, 3}}//two-dimensional array of another declarative way, internal and external type consistent var fslice []int                                  Declares a slice, and the array is removed from the length sslice: = []byte{1, 2, 3, 4}//Declare and initialize a slice tslice: = Arr2[0:2] The slice contains the arr[0],arr[1 in the array arr2], the Slice declares arr[n:m], and contains the elements from Arr[n to arr[m-1]fmt. PRINTLN ("test")}//the first letter lowercase method is the private method of the Func test () {FMT. PRINTLN ("Test")}