{"id":10008109,"date":"2023-08-17T14:00:40","date_gmt":"2023-08-17T06:00:40","guid":{"rendered":"https:\/\/blog.itmax.cn\/?p=10008109"},"modified":"2023-08-17T14:00:40","modified_gmt":"2023-08-17T06:00:40","slug":"go-%e5%b0%86%e5%a2%9e%e5%8a%a0%e5%86%85%e7%bd%ae%e7%9a%84%e9%9b%b6%e5%80%bc%e6%a0%87%e8%af%86%e7%ac%a6-zero%ef%bc%81","status":"publish","type":"post","link":"https:\/\/itmax.cn\/?p=10008109","title":{"rendered":"Go \u5c06\u589e\u52a0\u5185\u7f6e\u7684\u96f6\u503c\u6807\u8bc6\u7b26 zero\uff01"},"content":{"rendered":"

\u5927\u5bb6\u597d\uff0c\u6211\u662f\u714e\u9c7c\u3002<\/p>\n

\u5927\u5bb6\u5b66\u4e60\u548c\u4f7f\u7528 Go \u8bed\u8a00\u65f6\uff0c\u6709\u4e00\u4e2a\u795e\u5947\u7684\u6982\u5ff5\uff1a\u96f6\u503c\uff08zero-values\uff09\u3002\u96f6\u503c\u8fd9\u4e2a\u540d\u5b57\u662f\u5177\u4f53\u8c01\u8d77\u7684\uff0c\u53c8\u662f\u4ece\u54ea\u91cc\u5148\u5f00\u59cb\u558a\u8d77\u7684\uff0c\u5df2\u7ecf\u96be\u4ee5\u8003\u7a76\u4e86\u3002<\/p>\n

\u6bcf\u6b21\u6709\u65b0\u540c\u5b66\u521a\u5f00\u59cb\u8f6c\u8bed\u8a00\uff0c\u5de5\u7a0b\u4e0a\u603b\u4f1a\u63d0\u5230\u8fd9\u4e2a\uff0c\u60f3\u8981\u8bd5\u56fe\u6539\u53d8\u96f6\u503c\u3002\u53c8\u6216\u662f\u6ca1\u8003\u8651\u5230\uff0c\u4e00\u65e6\u7a0b\u5e8f\u7528\u4e86 0 \u4f5c\u4e3a default \u503c\uff0c\u53c8\u8981\u517c\u5bb9\u96f6\u503c\u7684\u95ee\u9898\u3002<\/p>\n

\u4eca\u5929\u7ed9\u5927\u5bb6\u5206\u4eab\u4e00\u4e2a\u5173\u4e8e\u96f6\u503c\u7684\u65b0\u63d0\u6848\uff0c\u76ee\u6d4b\u5df2\u7ecf\u516b\u4e5d\u4e0d\u79bb\u5341\u4e86\u3002<\/p>\n

\"\"<\/p>\n

\u5feb\u901f\u590d\u4e60\u96f6\u503c<\/h2>\n

\u57fa\u7840\u7c7b\u578b\u7684\u4f8b\u5b50\u5982\u4e0b\uff1a<\/p>\n

func main() {\n    var i int\n    var f float64\n    var b bool\n    var s string\n    fmt.Printf("%v %v %v %q\/n", i, f, b, s)\n}<\/code><\/pre>\n
\u8f93\u51fa\u7ed3\u679c\uff1a<\/p>\n
0 0 false ""\n<\/code><\/pre>\n
\u590d\u5408\u7c7b\u578b\u7684\u4f8b\u5b50\u5982\u4e0b\uff1a<\/p>\n
type Person struct {\n    Name   string\n    Age    int\n    Weight float64\n}\n\nfunc main() {\n    var p Person\n    var m map[int]string\n    var s []string\n\n    fmt.Printf("%#v\/n%#v\/n%#v\/n", p, m, s)\n}<\/code><\/pre>\n
\u8f93\u51fa\u7ed3\u679c\uff1a<\/p>\n
main.Person{Name:"", Age:0, Weight:0}\nmap[int]string(nil)\n[]string(nil)\n<\/code><\/pre>\n
\u7c7b\u578b\u548c\u96f6\u503c\u7684\u6620\u5c04\u8868\u683c\u5982\u4e0b\uff1a<\/p>\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
\u6570\u636e\u7c7b\u578b<\/th>\n\u96f6\u503c<\/th>\n<\/tr>\n<\/thead>\n
int, int8, int16, int32, int64<\/td>\n0<\/td>\n<\/tr>\n
uint, uint8, uint16, uint32, uint64<\/td>\n0<\/td>\n<\/tr>\n
uintptr<\/td>\n0<\/td>\n<\/tr>\n
float32, float64<\/td>\n0<\/td>\n<\/tr>\n
byte<\/td>\n0<\/td>\n<\/tr>\n
rune<\/td>\n0<\/td>\n<\/tr>\n
string<\/td>\n“” (empty string)<\/td>\n<\/tr>\n
complex64, complex128<\/td>\n(0,0i)<\/td>\n<\/tr>\n
arrays of non-nillable types<\/td>\narray of zero-values<\/td>\n<\/tr>\n
arrays of nillable types<\/td>\narray of nil-values<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
\u65b0\u63d0\u6848\uff1a\u9884\u58f0\u660e\u6807\u8bc6\u7b26 zero<\/h2>\n
\u80cc\u666f<\/h3>\n
\u4e8b\u60c5\u7684\u8d77\u56e0\u662f\uff1a@Nathan Cormier \u5728\u793e\u533a\u63d0\u4e86\u5410\u69fd\u548c\u63d0\u6848\u300aproposal: builtin: zero function<\/a>\u300b\uff1a<\/p>\n
\"\"<\/p>\n
\u4ed6\u8868\u793a\uff1aGo \u8bed\u8a00\u76ee\u524d\u63d0\u4f9b\u4e86\u51e0\u79cd\u83b7\u53d6\u7c7b\u578b\u96f6\u503c\u7684\u65b9\u6cd5\uff0c\u5982\u679c\u80fd\u6709\u4e00\u79cd\u7edf\u4e00\u7684\u65b9\u6cd5\u6765\u5b9e\u73b0\u8fd9\u4e00\u70b9\uff0c\u4ee3\u7801\u7684\u53ef\u8bfb\u6027\u4f1a\u66f4\u9ad8\u3002<\/p>\n
\u6709\u540c\u5b66\u6df1\u601d\uff0c\u54ea\u6765\u7684\u51e0\u79cd\uff1f\u5176\u5b9e\u53ef\u4ee5\uff1a<\/p>\n
var z MyType\nreturn z<\/code><\/pre>\n
\u8fd8\u53ef\u4ee5\uff1a<\/p>\n
return *new(MyType)<\/code><\/pre>\n
\u521d\u59cb\u5316\u7ed3\u6784\u4f53\u540e\u51fa\u6765\u7684\u90fd\u662f\u96f6\u503c\u3002<\/p>\n
\u7d27\u63a5\u7740\u5c31\u4f1a\u9047\u5230\u5f00\u5934\u63d0\u5230\u7684\u95ee\u9898\uff0c\u4f60\u600e\u4e48\u77e5\u9053\u8fd9\u662f\u96f6\u503c\uff0c\u8fd8\u662f\u7f3a\u7701\u503c\uff1f\u96be\u4ee5\u76f4\u63a5\u5224\u522b\u3002<\/p>\n
\u66f4\u91cd\u8981\u7684\u662f\uff0c\u8fd9\u4e0d\u592a\u7b26\u5408 Go \u7684\u8bbe\u8ba1\u54f2\u5b66\uff0c\u53c8\u662f\u591a\u79cd\u9014\u5f84\uff0c\u8fd8\u548c\u7f3a\u7701\u503c\u4ea7\u751f\u6df7\u6dc6\u3002\u663e\u7136\u548c\u4e3b\u6253\u5de5\u7a0b\u7684 Go \u7684\u53d1\u5c55\u8def\u5b50\u4e0d\u5408\u3002<\/p>\n
\u89e3\u51b3\u65b9\u6848<\/h2>\n
\u65b0\u589e zero \u6807\u8bc6\u7b26<\/h3>\n
\u8fd9\u6b21\u7ecf\u8fc7\u4e00\u756a\u6495\u626f\uff0c\u6700\u7ec8\u662f\u7531 Go \u6838\u5fc3\u56e2\u961f\u8d1f\u8d23\u4eba @Russ Cox \u51fa\u6765\u4e3b\u6301\u5927\u5c40\uff0c\u63d0\u51fa\u4e86\u65b0\u63d0\u6848\u5e76\u4e00\u8def\u5411\u524d\u3002<\/p>\n
\"\"<\/p>\n
Go \u5c06\u4f1a\u589e\u52a0\u4e00\u4e2a\u65b0\u7684\u9884\u5b9a\u4e49\u6807\u8bc6\u7b26 zero<\/code>\uff0c\u5b83\u662f\u4e00\u4e2a\u65e0\u7c7b\u578b\u7684\u96f6\u503c<\/strong>\uff0c\u9002\u7528\u4e8e\u6570\u7ec4\u548c\u7ed3\u6784\u4f53\u7c7b\u578b\u3002<\/p>\n
\u4ee5\u4e0b\u662f zero \u7684\u7c7b\u578b\u7b7e\u540d\uff1a<\/p>\n
\/\/ zero is a predeclared identifier representing the zero value\n\/\/ for array and struct types.\nvar zero Type<\/code><\/pre>\n
\u4ed6\u4e0d\u4f1a\u50cf nil \u4e00\u6837\u3002\u6211\u4eec\u53ef\u4ee5\u5bf9\u7167\u770b\u770b nil \u7684\u7c7b\u578b\u7b7e\u540d\uff1a<\/p>\n
\/\/ nil is a predeclared identifier representing the zero value for a\n\/\/ pointer, channel, func, interface, map, or slice type.\nvar nil Type \/\/ Type must be a pointer, channel, func, interface, map, or slice type<\/code><\/pre>\n
Nil \u53d7\u9650\u4e8e chan\u3001func\u3001interface\u3001map\u3001slice\u3001pointer \u7b49\u7c7b\u578b\u3002<\/p>\n
zero \u53ef\u8d4b\u503c\u6027\u89c4\u5219<\/h3>\n
zero<\/code> \u7684\u53ef\u8d4b\u503c\u6027\u89c4\u5219\u5982\u4e0b\uff1a<\/p>\n