{"id":10006758,"date":"2022-10-28T12:59:24","date_gmt":"2022-10-28T04:59:24","guid":{"rendered":"https:\/\/ityet.com\/?p=10006758"},"modified":"2022-10-28T12:59:24","modified_gmt":"2022-10-28T04:59:24","slug":"go-%e5%a4%a7%e4%bd%ac%e8%89%af%e5%bf%83%e5%8f%91%e7%8e%b0%ef%bc%8c%e6%84%bf%e6%84%8f%e7%bb%99-map-%e5%8a%a0%e6%b8%85%e9%99%a4%e4%ba%86%ef%bc%9f","status":"publish","type":"post","link":"https:\/\/itmax.cn\/?p=10006758","title":{"rendered":"Go \u5927\u4f6c\u826f\u5fc3\u53d1\u73b0\uff0c\u613f\u610f\u7ed9 map \u52a0\u6e05\u9664\u4e86\uff1f"},"content":{"rendered":"

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

\u4e00\u4e2a\u4e1c\u897f\u6765\u6765\u56de\u56de\u7684\u8ba8\u8bba\uff0c\u5173\u4e86\u53c8\u5f00\uff0c\u5173\u4e86\u540e\u5efa\u65b0\u7684\uff0c\u65b0\u7684\u88ab ban \u4e86\uff0c\u53c8\u53d1\u73b0\u65b0\u7684\u8bba\u636e\uff0c\u518d\u6253\u5f00\u65b0\u7684\u3002\u8fd9\u5728\u804c\u573a\u5de5\u4f5c\u4e2d\u5f88\u5e38\u89c1\uff0c\u5728 Go \u7684\u63d0\u6848\u8ba8\u8bba\u4e2d\uff0c\u4e5f\u51fa\u73b0\u4e86\u3002<\/p>\n

\u4eca\u5929\u8981\u7ed9\u5927\u5bb6\u4ecb\u7ecd\u7684\u662f map \u5728 NaN \u4e0a\u7684\u4e00\u4e2a\u5c0f\u4e89\u8bae\u548c\u53ef\u80fd\u5373\u5c06\u51fa\u73b0\u7684 API \u589e\u52a0\u3002<\/p>\n

\u80cc\u666f\u548c\u8003\u9898<\/h2>\n

NaN \u662f\u4ec0\u4e48<\/h3>\n

\u5728\u8ba1\u7b97\u673a\u79d1\u5b66\u4e2d\uff0c\u6709\u4e00\u4e2a\u795e\u5947\u7684\u503c,\u53eb\u505a\uff1aNaN\uff08Not a Number\uff0c\u975e\u6570\uff09\u3002\u5b83\u662f\u6570\u503c\u6570\u636e\u7c7b\u578b\u7684\u4e00\u7c7b\u503c\uff0c\u8868\u793a\u672a\u5b9a\u4e49\u6216\u4e0d\u53ef\u8868\u793a\u7684\u503c<\/strong>\u3002\u5e38\u5728\u6d6e\u70b9\u6570\u8fd0\u7b97\u4e2d\u4f7f\u7528\u3002\u9996\u6b21\u5f15\u5165 NaN \u7684\u662f 1985 \u5e74\u7684 IEEE 754 \u6d6e\u70b9\u6570\u6807\u51c6\u3002<\/p>\n

\u5728\u4e0e NaN \u503c\u7684\u5b58\u50a8\u548c\u6bd4\u8f83\u65f6\uff0c\u4f1a\u6709\u95ee\u9898\u3002\u56e0\u4e3a\u5224\u65ad\u4e00\u4e2a\u503c\u662f\u5426\u4e3a NaN \u65f6\uff0c\u4e0d\u80fd\u901a\u8fc7\u5224\u65ad x=NaN \u6216 x\u2260NaN \u6765\u8fdb\u884c\u6bd4\u8f83\u3002\u4f46\u56e0\u4e3a NaN \u6c38\u8fdc\u4e0d\u7b49\u4e8e\u5176\u81ea\u8eab\uff0c\u56e0\u6b64\u53ef\u901a\u8fc7\u5224\u65ad x=x \u6216 x\u2260x \u6765\u5224\u65ad x \u662f\u5426\u4e3a NaN \u503c\uff0c\u5c06\u4f1a\u5206\u522b\u8fd4\u56de False \u548c True\u3002<\/p>\n

\u5f53 NaN \u4e0e\u53e6\u4e00\u4e2a\u6d6e\u70b9\u6570 x\uff08\u5176\u4e2d x \u53ef\u4e3a\u6b63\u5e38\u503c\u3001\u6b63\u8d1f\u65e0\u7a77\u5927\u6216 NaN\uff09\u8fdb\u884c\u6bd4\u8f83\u65f6\uff0c\u6bd4\u8f83\u7ed3\u679c\u5982\u4e0b\uff1a<\/p>\n\n\n\n\n\n\n\n\n\n\n
\u6bd4\u8f83<\/th>\n\u7ed3\u679c<\/th>\n<\/tr>\n<\/thead>\n
NaN \u2265 x<\/td>\nFalse<\/td>\n<\/tr>\n
NaN \u2264 x<\/td>\nFalse<\/td>\n<\/tr>\n
NaN > x<\/td>\nFalse<\/td>\n<\/tr>\n
NaN < x<\/td>\nFalse<\/td>\n<\/tr>\n
NaN = x<\/td>\nFalse<\/td>\n<\/tr>\n
NaN \u2260 x<\/td>\nTrue<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

\u8fd9\u91cc\u7684\u7406\u89e3\u5bf9\u4e8e\u4e0b\u9762\u7684\u8003\u9898\u5f88\u91cd\u8981\u3002<\/p>\n

Go IEEE-754 \u8003\u9898<\/h3>\n

\u5728 Go101 \u4e0a\u770b\u5230\u4e00\u9053\u5173\u4e8e IEEE-754 \u6d6e\u70b9\u6570\u7684\u9898\uff0c\u6211\u8fd9\u91cc\u5f15\u7528\u9898\u76ee\uff0c\u4ee5\u4e0b\u4ee3\u7801\u8f93\u51fa\u4ec0\u4e48\uff1f<\/p>\n

\u5982\u4e0b\u4ee3\u7801\uff1a<\/p>\n

package main\n\nimport "math"\n\nfunc main() {\n    a, b, c := 2.0, 1.0, 0.0\n    x, y := a\/c, b\/c     \/\/ infinity\n    n := math.NaN()      \/\/ not a number\n    m := math.Sqrt(-1.0) \/\/ not a number\n    println(x == y, m == n)\n}<\/code><\/pre>\n