Go常量Go變量Go數(shù)值Go數(shù)組Go字典Go方法Go結構體Go接口Go字符串格式化Go自定義排序GoDeferGoforGoJSON支持GoLineFiltersGo狀態(tài)協(xié)程GoPanicGorange函數(shù)GoSHA1GoSwitch語句GoURL解析GoGo超時Go打點器Go文件Go工作池GoGoGo計時器 oworldGo命令行參數(shù)GoGoGoGoGoGoGoGo寫入文件Go信號處理Go指針原作者 譯者：@jemygraw@everyx僅用于學習交流之用，用于商業(yè)用途。（如果給我打賞，我是不會的內Go常量Go變量Go數(shù)值Go數(shù)組Go字典GoGo結構體Go接口Go字符串格式化Go自定義排序GoBase64編碼GoDeferGoExit.mdGoforGoJSON支持GoLineFiltersGo狀態(tài)協(xié)程GoPanicGorange函數(shù)GoSHA1GoString與Byte切片之間的轉換GoSwitch語句GoURL解析GoGo超時Go打點器Go工作池GoGoGo計時器 oGoGoGoGoGoGoGoGoGo寫入文件Go信號處理Go指針Go常Go常使 關鍵字來定義常量packagepackageimport"fmt""constconstsstring=funcmain()constn=常量表達式可以執(zhí)行任意精度數(shù)學計算constd=3e20/n}Go變Go變使 關鍵字來定義變量intint8int16int32uintuint8uint16uint32uint64uintptrbyte//uint8的別名float32complex64packagemainimport"fmt"funcpackagemainimport"fmt"funcmain()`var`varastring=你一次可以定義多個變量varb,cint=1,2fmt.Println(b,c)Go會推斷出具有初始值的變量的類型vard=truevareintf:=}1GoGo數(shù)packagemainimport"fmt"funcpackagemainimport"fmt"funcmain()字符串可以使用"+"fmt.Println("go"+fmt.Println("1+11+1)fmt.Println("7.0/3.0=",fmt.Println(true&&false)fmt.Println(true||false)}1+1=7.0/3.0=GoGo數(shù)組是一個具有相同數(shù)據(jù)類型的元素組成的

packagemainimport"fmt"funcmain(){//對于整數(shù)，零值就是0vara[5]intfmt.Println("emp:"a)"array[indexvalue"a[4]=100b:=[5]int{1,2,3,4,//來獲 vartwoDfori:=0;i<2;{forj:=0;j<3;{twoD[i][j]=i+}}fmt.Println("2d:",}emp:emp:[0000set:[0000get:len::] 示例packagepackagemainimportfuncmain()vara=new([5]int)fmt.Println(a,len(a))}functest(a{a[1]=}&[0&[05000]示例packagepackageimport"fmt"funcmain()a:={0,{8,}b:={0,{8,}fmt.Println(a,len(a))fmt.Println(b,}typeUser{IdNameName}[{0[{0User0}{8User8}][0x1f2161300x1f216140]GoGopackagemainimport"fmt"funcmain()創(chuàng)建一個字典可以使用內置函數(shù)"make(map[鍵類型]值類型)"m:=make(map[string]int)m["k1"]=m["k2"]=獲取一個鍵的值"name[key]".v1:=m["k1"]fmt.Println("v1:",delete(m,_,ok:=你可以用n:=map[string]int{"foo":1,"bar":fmt.Println("map:",}map:map:map[k1:7k2:13]v1:7len:ok:falsemap:map[foo:1Go數(shù)Gopackagepackagemainimportfuncplus(aint,bint)intGo需要使用return語句顯式地返回值returna+b}funcmain()名稱(參數(shù)列表)"resplus(1fmt.Println("1+2=",}1+21+2=GoGoimport"fmt"typerectstruct{width,height}這個area方法有一個限定類型func(r*rect)area(){returnr.width*}//那么在該方 func(rrect)perim(){return2*r.width+}funcmain()r:=rect{width:10,height:fmt.Println("area:", rp:=fmt.Println("area:",}area:area:perim:area:perim:示例MethodMethod MethodMethodimport)funcmain()p {2,varf1func(int)=p.test.test(p,varf2func(f2(p,4),int)} {IdintNamestring}func)test(x{fmt.Println("Id:",this.Id,"Name",this.Name)fmt.Println("x=",x)}Id:Id:2x=Id:2x=Id:2x=Id:2x=示例使 import)funcmain()p:=Student{{2, "},} {IdintNamestring}typeStudent{Score}func){ }func(thisStudent){fmt.Println("student}studentstudentGo構Go構packagemainimport//這 {namestringageint}funcmain() {name:"Alice",age: {name: {name:"Ann",age://使用點號(.) s {name:"Sean",age://結構體指針也可以使用點號(.) Go語言會自動識別出來sp:=&s結構體成員變量的值是可以改變的sp.age=51}{Bob{Bob{Alice{FredGo包Go示例packagepackagemainimport //這個返回 funcintSeq()func(){i:=returnfunc(){i+=return}}funcmain()//nextInt:=調用幾次nextInt，看看閉包的效果newInts:=}11231示例packagepackagemainimportfuncmain()add10add10closure(10)//其實是構造了一個加10add20:=closure(20)}funcclosure(xint)func(yint){returnfunc(yint)int{returnx+y}}示例packagemainimport"fmt"funcpackagemainimport"fmt"funcmain()varfs[]func()fori:=0;i<3;i++fs=append(fs,func(){return}for_,f:=range{fmt.Printf("%p=%v\n",f,}}0x4012000x401200=0x401200=0x401200=示例packagepackagemainimportfuncfuncadder()func(int){sum:=returnfunc(xint){sum+=xreturn}}funcmain()result:=fori:=0;i<10;{}}00GoGopackageimport"fmt"typegeometry{area()float64perim()float64}typesquare{width,height}typecircle{radius}func(ssquare)area(){returns.width*}func(ssquare)perim(){return2*s.width+}func(ccircle)area()float64returnmath.Pi*c.radius*}func(ccircle)perim(){return2*math.Pi*}////在measure函 funcmeasure(g{fmt.Println(g)}funcmain()s:=square{width:3,height:4}c:=circle{radius:5}//////函數(shù)的參數(shù)}{3{3Go字符串操作Go字符串操作函packageimports"strings"import"fmt"varp=fmt.Printlnfuncmain(){p("Contains:",s.Contains("test", ",s.Count("test",p("HasPrefix:",s.HasPrefix("test",p("HasSuffix:",s.HasSuffix("test", ",s.Index("test", ",s.Join([]string{"a","b"},"-")) ",s.Repeat("a",5)) ",s.Replace("foo","o","0",- ",s.Replace("foo","o","0", ",s.Split("a-b-c-d-e","-")) ",s.ToLower("TEST")) p("Len:", p("Char:", }Contains:Contains:trueCount:2HasPrefix:trueHasSuffix:trueIndex:1Join:a-Repeat: [abcd Len:Len:Char:Go字符串格式packageimport"os"typepoint{x,y}funcmain()p:=point{1,`%#v`格式化輸出將輸出一個值的Go語法表示方式。fmt.Printf("%#v\n",p)//格式 浮點型數(shù)值也有幾種格式化方法。最基本的一種是`%f`fmt.Printf("%f\n",78.9)//`%e`和`%E`使用科 fmt.Printf("%e\n",輸出像Go源碼中那樣帶雙引號的字符串，需使用`%q`fmt.Printf("%q\n","\"string\"")`%x`以16進制輸出字符串，每個字符串的字節(jié)用兩個字符輸出fmt.Printf("%x\n","hexthis")fmt.Printf("|%6d|%6d|\n",12,//Toleft-justify,usethe`-`flag.fmt.Printf("|%-6.2f|%-6.2f|\n",1.2,3.45)fmt.Printf("|%6s|%6s|\n","foo",//s:=fmt.Sprintf("a%s","string")你也可以使用`Fprintf`來將格式化后的值輸出到`io.Writers`fmt.Fprintf(os.Stderr,"an%s\n","error")}{1{1{x:1! |1.20||1.20|3.45 astringananpackagepackageimport"fmt"數(shù)組定義了一個別名ByLengthtypeByLength[]string//func(sByLength)Len(){return}func(sByLength)Swap(i,j{s[i],s[j]=s[j],}func(sByLength)Less(i,jint){returnlen(s[i])<}sort包的Sort方法來排序funcmain(){fruits:=[]string{"peach","banana","kiwi"}}[kiwi[kiwipeachpackageimportb64import"fmt"funcmain() data:="abc123!?$*&()'-sEnc:= 如果你不知道輸入是否是正確的//編碼，你需要檢測一 錯sDec,_:=uEnc:=uDec,_:=b64.URLEncoding.DecodeString(uEnc)}+-+-。

Gopackagepackageimport"os"funcmain()//f:=//f:=defercloseFile(f)}funccreateFile(pstring)f,err:=os.Create(p)iferr!=nil{}return}funcwriteFile(ffmt.Fprintln(f,"data")}funccloseFile(f}Go packagepackageimport"os"funcmain()defer}gogogogoexitexitstatus $$$echo$?Gofor循packagemainimport"fmt"funcpackagemainimport"fmt"funcmain()i:=fori<=3i=i+1}forj:=7;j<=9;{}for}}1123789packagemainimport"fmt"funcpackagemainimport"fmt"funcmain()if7%2==0fmt.Println("7is}elsefmt.Println("7is}只有ifif8%4==0fmt.Println("8isdivisibleby}ifnum:=9;num<{fmt.Println(num,"is}elseifnum<{fmt.Println(num,"has1}elsefmt.Println(num,"hasmultiple}isisisdivisiblebyhas1GoJSON支GoJSON支packageimport"encoding/json"import"fmt"import//我們使用兩個結構體來演示自定義數(shù)據(jù)類型的JSON數(shù)據(jù)編碼 typeResponse1{PageintFruits[]string}typeResponse2struct Fruits[]string`json:"fruits"`}funcmain()首先我們看一下將基礎數(shù)據(jù)類型編碼為JSON數(shù)據(jù)bolB,_:=json.Marshal(true)intB,_:=json.Marshal(1)fltB,_:=json.Marshal(2.34)strB,_:=json.Marshal("gopher")slcD:=[]string{"apple","peach","pear"}slcB,_:=json.Marshal(slcD)mapD:=map[string]int{"apple":5,"lettuce":7}mapB,_:=json.Marshal(mapD)為JSONres1D&Response1{Page:Fruits:[]string{"apple","peach","pear"}}res1B,_:=json.Marshal(res1D)res2D&Response2{Fruits:[]string{"apple","peach","pear"}}res2B,_:=json.Marshal(res2D)//現(xiàn)在我們看 byt:=//我們需要提供一個變量 //保 vardat iferr:=json.Unmarshal(byt,&dat);err!={}//為了使 //它們合適的類型，例如 num:=dat["num"].(float64) strs:=str1:=strs[0].(string)//我們還可以將 str:=`{"page":1,"fruits":["apple",res:=&Response2{}json.Unmarshal([]byte(str),&res)////enc:=d:=map[string]int{"apple":5,"lettuce":7}}map[num:6.13strs:[ab]]a&{1[applepeach]}GoLineGoLineGoLineGoLineLineFilters翻譯一下大概是行數(shù)據(jù)過濾器。簡單一點就是一個程序從標準輸入stdin數(shù)據(jù)，然后處理一下，的GoLineFilters。import()funcmain() scanner:=forscanner.Scan()ucl:=}iferr:=scanner.Err();err!={fmt.Fprintln(os.Stderr,"error:",err)}}ooworldOhowareyouHOWAREGo態(tài)Goimport() typereadOp{keyintrespchanint}typewriteOp{keyintvalintrespchan}funcmain() varopsint64=//reads和writes通道將被其他協(xié)程用來從 reads:=make(chanwrites:=make(chan//gofunc()varstate=make(map[int]int)for{selectcaseread:=<-read.resp<-state[read.key]casewrite:=<-writes:state[write.key]=write.valwrite.resp<-true}}//這里啟動了100個 forr:=0;r<100;{gofunc(){for{read:=key:rand.Intn(5),resp:make(chanint)}reads<-atomic.AddInt64(&ops,1)}}我們開啟10forw:=0;w<10;{gofunc(){for{write:=&writeOp{val:rand.Intn(100),resp:make(chanbool)}writes<-atomic.AddInt64(&ops,1)}}讓協(xié)程運行1最后輸出操作數(shù)量opsopsFinal:=fmt.Println("ops:",}ops:ops:運行這個程序，我們會看到基于協(xié)程的狀態(tài)管理每秒可以處理800000個操作。對于這個例子來講，基于協(xié)程當然你可以選擇使用任意GoGopackagemainimport"os"funcpackagemainimport"os"funcmain(){panic("a_,err:=iferr!=nil{}}panic:aproblemgoroutinepanic:aproblemgoroutine1[running]:c.c:266+0xc8D:/GoDoc/go_panic.go:8+0x58exitstatus2Gorange函Gorange函packagemainimport"fmt"funcmain()nums:=[]int{2,3,sum:=for_,num:=range{sum+=}fori,num:=range{ifnum==3{}}kvs:=map[string]string{"a":"apple","b":fork,v:=rangekvs{fmt.Printf("%s->%s\n",k,v)}fori,c:=range{fmt.Println(i,}}sum:sum:index:->->011GoSHA1 Go packagepackageimport"fmt"funcmain()s:="sha1this生成一個hash的模式是//h:=////bs:=}sha1thisstringsha1thisstringGoString與Byte切片之間的轉packagemainimport"fmt"funcpackagemainimport"fmt"funcmain()s1:=b1:=fmt.Println(b1)//[979899s2中文b2:=fmt.Println(b2)[228184173230150135]unicode，每個中文字符會由三個byter1:=fmt.Println(r1[979899100]r2:=fmt.Println(r2[2001325991]}GoSwitch語GoSwitch語packageimport"fmt"importfuncmain()基礎的switchi:=fmt.Print("write",i,"as")switchi{casecase2:case3:}//switch{casetime.Saturday,fmt.Println("it'stheweekend")fmt.Println("it'sa}t:=switchcaset.Hour()<12:fmt.Println("it'sbeforenoon")fmt.Println("it'safter}}write2astwoit'saweekdayit'swrite2astwoit'saweekdayit'sbeforenoonGoURL解GoURL解packageimport"fmt"import"net/url"importfuncmain() s:= //解析URL， u,err:=url.Parse(s)iferr!=nil{}//可以直 p,_:=u.User.Password()h:=strings.Split(u.Host,":")這里我們解析出路徑和`#`后面的片段//字符串切片作為valuem,_:=url.ParseQuery(u.RawQuery)}Go歷Gopackagemainimport"fmt"funcpackagemainimport"fmt"funcmain()我們遍歷queue通道里面的兩個數(shù)據(jù)queue:=make(chanstring,2)queue<-"one"queue<-"two"http://forelem:=range{}}Go行Gopackagepackagemainimportfuncf(fromstring)fori:=0;i<3;{fmt.Println(from,":",}}funcmain()假設我們有一個函數(shù)叫做//運行使用gogo//你也可以 gofunc(msg{讓mainvarinput}directdirect:direct:direct:goroutine:goroutine:goroutine:2Go行通道packagemainimport"fmt"funcpackagemainimport"fmt"funcmain()使用`make(chan數(shù)據(jù)類型)`來創(chuàng)建一個Channel的類型就是它們所傳遞的數(shù)據(jù)的類型messages:=make(chanstring)gofunc(){messages<- " messages通道的數(shù)據(jù)msg:=<-messages}GoGopackageimport"fmt"funcmain()在這個例子中，假設我們執(zhí)行了一個外部調用，2秒之后將結果寫入c1c1:=make(chanstring,1)gofunc()time.Sleep(time.Second*2)c1<-"result1"這里使用select來實現(xiàn)超時，`resc1`-`resc1`超過1秒沒有執(zhí)行的話select{caseres:=<-c1:case<-time.After(time.Second*1):fmt.Println("timeout1")}//如 c2:=make(chanstring,gofunc()time.Sleep(time.Second*2)c2<-"result2"selectcaseres:=<-c2:case<-time.After(time.Second*3):fmt.Println("timeout2")}}timeouttimeoutresultGo誤Gopackageimport"fmt"funcf1(argint)(int,{ifarg==42errors.New使用錯誤信息作為參數(shù)，構建一個基本的錯誤return-1,errors.New("can'tworkwith42")}returnarg+3,}typeargError{argintprobstring}func(e*argError)Error()stringreturnfmt.Sprintf("%d-%s",e.arg,}funcf2(argint)(int,{ifarg==42return-1,&argError{arg,"can'tworkwith}returnarg+3,}funcmain()//for_,i:=range[]int{7,42}ifr,e:=f1(i);e!={fmt.Println("f1failed:",}}elsefmt.Println("f1worked:",}}for_,i:=range[]int{7,42}ifr,e:=f2(i);e!={fmt.Println("f2failed:",}elsefmt.Println("f2worked:",}}//_,e:=ifae,ok:=e.(*argError);}}f1f1worked:f1failed:can'tworkwith42f2worked:10f2failed:42-can'tworkwithitcan'tworkwithGo點TickerTickerpackagepackageimport"fmt"funcmain()ticker:=time.NewTicker(time.Millisecond*gofunc()fort:=range{fmt.Println("Tickat",}//接收數(shù)據(jù)，這里 time.Sleep(time.Millisecond*1500)}TickTickat2014-02-18Tickat2014-02-18Tickat2014-02-18Ticker Go歸Gopackagepackagemainimportfact函數(shù)不斷地調用自身，直到達到基本狀態(tài)fact(0)funcfact(nint)int{ifn==0return}returnn*fact(n-}funcmain()}Go文Go文import() funccheck(e{ife!=nil{}}funcmain()//最基本的文件讀寫任務就是把整個文件的內容 dat,err:=ioutil.ReadFile("/tmp/dat")//有的時候你 //f,err:=//從這個文件 //最 b1:=make([]byte,5)n1,err:=f.Read(b1)fmt.Printf("%dbytes:%s\n",n1,//那個位置開 數(shù)o2,err:=f.Seek(6,b2:=make([]byte,2)n2,err:=f.Read(b2)fmt.Printf("%dbytes@%d:%s\n",n2,o2, o3,err:=f.Seek(6,b3:=make([]byte,n3,n3,err:=io.ReadAtLeast(f,b3,2)fmt.Printf("%dbytes@%d:%s\n",n3,o3,_,err=f.Seek(0,//`bufio`包提供了緩 r4:=b4,err:=r4.Peek(5)fmt.Printf("5bytes:%s\n", }

iamjemywhoareyouwhatdoyou5 2bytes@6:2bytes@6:5 Go作Go作packageimport"fmt" //funcworker(idint,jobs<-chanint,resultschan<-{forj:=rangejobsfmt.Println("worker",id,"processingjob",j)results<-j*}}funcmain()這里我們定義兩個通道，一個jobs，一個resultsjobs:=make(chanint,100)results:=make(chanint,jobs通道里面還沒有工作任務forw1w3w+goworker(w,jobs,}forj:=1;j<=9;{jobs<-}fora:=1;a<=9;a++}workerworker1processingjobworker2processingjobworker3processingjobworker1processingjobworker3processingjobworker2processingjobworker1processingjobworker3processingjobworkerworker2processingjobGo閉Gopackagemainimport//funcmain()jobs:=make(chanint,5)done:=make(chanbool)這里是數(shù)據(jù)接收端協(xié)程，它重復使用`jmorejobs`如果所有數(shù)據(jù)接收完成，那么向done通道寫入truegofunc(){forj,more:=<-jobsifmore{fmt.Println("receivedjob",}elsefmt.Println("receivedalljobs")done<-true}}forj:=1;j<=3;{jobs<-jfmt.Println("sentjob",j)}fmt.Println("sentalljobs")}sentsentjobreceivedjobsentjobsentjob3sentalljobsreceivedjobreceivedjob3receivedreceivedjob3receivedalljobspackagepackagemainimport這個函數(shù)的返回值為兩個intfuncvals()(int,int){return3,}funcmain()獲取函數(shù)的兩個返回值a,b:=vals()_,c:=}3377GopackagepackagemainimporttypeCallbackfunc(x,yint)funcmain()x,y:=1,fmt.Println(test(x,y,}functest(x,yint,callbackCallback){returncallback(x,}funcadd(x,yint){returnx+}33Go函數(shù)命名返Go函數(shù)命名返回

packagepackagemainimportfuncsplit(sumint)(x,y{x=sum*4/9y=sum-x}funcmain()}77GoGoimport()funcmain()這個例子的狀態(tài)就是一個varstate=varmutex=ops將對狀態(tài)的操作進行計數(shù)varopsint64=0//這里我們啟動100個 forr:=0;r<100;{gofunc()total:=0for{//對于每 //唯一 //來 key:=rand.Intn(5)total+=state[key]atomic.AddInt64(&ops,1) //手動 }}//同樣我們使用10個 forw:=0;w<10;{gofunc(){for{key:=valval:=rand.Intn(100)state[key]=valatomic.AddInt64(&ops,1)}}//opsFinal:=atomic.LoadInt64(&ops)fmt.Println("ops:",opsFinal)//最后鎖定并輸出狀態(tài)fmt.Println("state:"state)}ops:ops:state:map[0:842:203:181:65Go境Gopackageimport"os"import"fmt"funcmain(){//////os.Setenv("FOO",這里我們打印所有的keyfor_,e:=range{pair:=strings.Split(e,"=")}}CHECKFIX1436934Go合Gopackageimport"fmt"返回t在vs中第一次出現(xiàn)的索引，如果沒有找到t，返回－1funcIndex(vs[]string,tstring)int{fori,v:=range{ifv==treturn}}return-}//如果t存在于vs中，那么返回true，否則falsefuncInclude(vs[]stringtstringboolreturnIndex(vs,t)>=}//那么返回true，否則funcAny(vs[]string,ffunc(string)bool){for_,v:=rangevs{iff(v){return}}return}//那么返回true，否則返回funcAll(vs[]string,ffunc(string)bool){for_,v:=rangevs{if!f(v){return}}return}//返回truefuncFilter(vs[]string,ffunc(string)bool){vsf:=make([]string,0)for_,v:=rangevs{iff(v)vsf=append(vsf,}}return}funcMap(vs[]string,ffunc(string)string){vsm:=make([]string,len(vs))fori,v:=rangevs{vsm[i]=}return}funcmain()varstrs=[]string{"peach","apple","pear",fmt.Println(Index(strs,"pear"))fmt.Println(Include(strs,"grape"))fmt.Println(Any(strs,func(vstring)bool{returnstrings.HasPrefix(v,fmt.Println(All(strs,func(vstring){returnstrings.HasPrefix(v,fmt.Println(Filter(strs,func(vstring){returnstrings.Contains(v,//上面的例子都使 }22[peachapplepear][PEACHAPPLEPEARPLUM]Go時Go時packagepackageimport"fmt"funcmain()這里的timer將等待2timer1:=time.NewTimer(time.Second*//typeTicket//C<-fmt.Println("Timer1//timer2:=gofunc()fmt.Println("Timer2stop2:=timer2.Stop()ifstop2{fmt.Println("Timer2}}TimerTimer1Timer2Go程Gopackageimport"fmt"import"os/exec"funcmain()//我們從一個簡 //函數(shù)創(chuàng)建了 dateCmd 生的話，`dateOut`將保存date的信息dateOut,err:=dateCmd.Output()iferr!=nil{}fmt.Println(">date") //grepCmd mand("grep", //向進程寫入數(shù)據(jù)，然 grepIn,_:=grepOut,_:=grepCmd.StdoutPipe() ogrep\ngoodbyegrep"))grepBytes,_:=ioutil.ReadAll(grepOut)//`StderrPipe`的結果fmt.Println(">grep //觸發(fā)一個完 lsCmd mand("bash","-c","ls-a-l-lsOut,err:=lsCmd.Output()iferr!=nil{}}fmt.Println(">ls-a-l-h")}WedOct1009:53:11PDT> ols-a-l-drwxr-xr-x4mark136BOct316:29drwxr-xr-x91mark3.0KOct312:50-rw-r--r--1mark1.3KOct316:28spawning-Go packagepackageimport"os"funcmain()binary,lookErr:=iflookErr!=nil{}args:=[]string{"ls","-a","-l","-env:=//錯誤發(fā)生 execErr:=syscall.Exec(binary,args,ifexecErr!=nil{}}totaltotaldrwxr-xr-x4mark136BOct316:29drwxr-xr-x91mark3.0KOct312:50-rw-r--r--1mark1.3KOct316:28execing-Go經(jīng)典opackagepackagemainimportfuncmain()}o$ls$ls$gobuild $ $./el_01_ oworld為了使一個go文件能夠編譯為可執(zhí)行文件，包名必須是main 出 oworld"字符串

func

gorun gorungogobuild

Go可變長參數(shù)列packagepackagemainimportfuncsum(nums{fmt.Print(nums,"")total:=0for_,num:=range{total+=}}funcmain()sum(1,sum(1,2,nums:=[]int{1,2,3,4}}[1[12][123][1234]gogo

使 packagepackageimport"os"funcmain() argsWithProg:=os.ArgsargsWithoutProg:=os.Args[1:]arg:=}go在運行該程序的時候，需要首先 go$$gobuildcommand-line-$mand-line-argumentsabcd[mand-line-argumentsabcd][abcd]cGo命令行參數(shù)wc-Go命令行參wc-

中 就是一個命令行--

packageimport"fmt"funcmain()//基礎的標 wordPtr:=flag.String("word","foo","anumbPtr:=flag.Int("numb",42,"anboolPtr:=flag.Bool("fork",false,"a//需要把該變量的地址傳遞給 varsvarflag.StringVar(&svar,"svar","bar","astring//當所有的 //后的選項值fmt.Println("word:"*wordPtr)fmt.Println("numb:"*numbPtr)fmt.Println("fork:"fmt.Println("svar:",svar)fmt.Println("tail:",flag.Args())}gogobuildcommand-line$$mand-line-flags-word=opt-numb=7-fork-word:optnumb:7tail:[]$$mand-line-flags-word:optnumb:42svar:bartail:[]$$mand-line-flags-word=opta1a2word:optnumb:42svar:bartail:[a1a2$$mand-line-flags-word=opta1a2a3-word:optnumb:42svar:bartrailing:[a1a2a3-使 或 $$mand-line-flags-Usage -fork=false:a-numb=42:an-svar="bar":astring-word="foo":a$$mand-line-flags-flagprovidedbutnotdefined:-watUsageof./go_cmd_flag:-fork=false:-fork=false:a-numb=42:an-svar="bar":astring-word="foo":aGoGopackagepackageimport"fmt"importfuncmain()//切片內容，而不是返回一個新的切片strs[]string{"c""a""b"}fmt.Println("Strings:",strs)ints:=[]int{7,2, 我們還可以檢測切片是否已經(jīng)排序好s:=sort.IntsAreSorted(ints)fmt.Println("Sorted:",s)}Strings:Strings:[abc]Ints:[247]Sorted:trueGoGopackagemainimport"fmt"funcmain(){//這里我們創(chuàng)建了一個長度為 默認為零值，對于字符串就是""s:=make([]string,s[0]=s[1]=s[2]=s=append(s,s=append(s,"e",c:=make([]string,copy(c,s)fmt.Println("cpy:",c)//切片還支持一個取切片的操作////l:=l=ll=//我們可以同時 t:=[]string{"g","h","i"}fmt.Println("dcl:",t)//我們也可以創(chuàng)建 twoD:=make([][]int,3)fori:=0;i<3;i++{innerLen:=i+1twoD[i]=make([]int,forj:=0;j<innerLen;j++{twoD[i][j]=i+j}}fmt.Println("2d:",}emp:emp:[set:[abc]get:clen:apd:[abcdef]cpy:[abcdef]sl1:[cde]sl2:[abcde]sl3:[cdef]dcl:[ghi]2d:[[0][12][23

或者推斷長度標志 packagepackageimport"fmt"funcmain(){s1:=make([]int,0)}functest(s{s=append(s,}packagepackagemainimportfuncmain()s1:=make([]int,0)s1=test(s1)}functest(s[]int){s=append(s,3)returns}示例packagemainimport"fmt"funcpackagemainimport"fmt"funcmain()s1:=make([]int,3,fmt.Println("s1=",s1,len(s1),cap(s1))s2:=append(s1,1,2,3)fmt.Println("s1=",s1,len(s1),fmt.Println("s2=",s2,len(s2),cap(s2))s3:=append(s2,4,5,6)fmt.Println("s1=",s1,len(s1),fmt.Println("s2=",s2,len(s2),fmt.Println("s3=",s3,len(s3),}s1=s1=[000]3s1=[000]3s2=[000123]6s1=[000]3s2=[000123]6s3=[000123456]9示例packagepackagemainimportfuncmain()s1:=[]int{0,1,2,3,4,5,6,7,8,s2:=make([]int,3,20)varnintn=copy(s2,fmt.Println(n,s2,len(s2),s3:=fmt.Println(n,s3,len(s3),n=copy(s3,s1[1:5])fmt.Println(n,s3,len(s3),cap(s3))}33[012]33[45]22[12]2Go請求處理頻率控Go請求處理頻率控packageimport"fmt"funcmain()//發(fā)送5個數(shù)據(jù)，然后關閉requests通道requests:=make(chanint,5)fori:=1;i<=5;i++{requests<-}limiter:=time.Tick(time.Millisecond* forreq:=rangerequestsfmt.Println("request",req,}//就允許同時處理3burstyLimiter:= .Time,fori:=0;i<3;{burstyLimiter<-}gofunc()fort:=rangetime.Tick(time.Millisecond*{burstyLimiter<-}//則每隔200毫秒處理一次burstyRequestsmake(chanint5)fori:=1;i<=5;i++{burstyRequests<-}}forreq:=rangeburstyRequestsfmt.Println("request",req,}}1234512345GoGopackageimport"fmt"importfuncmain()p:=從獲取當前時間開始now:=time.Now()then:=time.Date(2009,11,17,20,34,58,651387237,//輸出當天 Sub方法返回兩個時間的間隔(Duration)diff:=now.Sub(then)可以以不同的單位來計算間隔的大小}2014-03-022014-03-022009-11-17-03-022005-08-05Go間Go間packagepackageimport"fmt"importfuncmain()now:=secs:=now.Unix()nanos:=now.UnixNano()微秒手動除以一個數(shù)值來獲取毫秒millis:=nanos/1000000//為對應的時間fmt.Println(time.Unix(secs,0)),}2014-03-022014-03-0282014-03-02 2014-03-02 Go時間格式化和解Go時間格式化和解packageimport"fmt"importfuncmain()p:=t:=Formatp(t.Format("MonJan_215:04:052006"))t.Year(),t.Month(),t.Hour(),t.Minute(),t1,etime.Parse(withNanokitchen:=t2,e:=time.Parse(kitchen,"8:41PM")Parse將返回一個錯誤，如果所輸入的時間格式不對的話ansic:="MonJan_215:04:052006"_,e=time.Parse(ansic,"8:41PM")}MonMar322:39:312012-11-01-01-01 parsingtime"8:41PM"as"MonJan_215:04:052006":cannotparse"8:41PM"as"Mon"Go 提供了數(shù)字解析功能packagepackageimport"fmt"funcmain()f,_:=strconv.ParseFloat("1.234",i,_:=strconv.ParseInt("123",0,d,_:=strconv.ParseInt("0x1c8",0,64)u,_:=strconv.ParseUint("789",0,Atoi是解析10進制整型的快捷方法k,_:=strconv.Atoi("135")_,e:=}strconv.ParseInt:parsing"wat":invalidGo機Go packageimport"fmt"funcmain()例如`rand.Intn`返回一個整型隨機數(shù)n，0<=n<100fmt.Print(rand.Intn(100),",")`rand.Float64`返回一個`float64`//`0.0<=f<//例如`5.0<=f<10.0`fmt.Print((rand.Float64()*5)+5fmt.Print((rand.Float64()*5)+5)//為了使隨機數(shù) s1