"# LUA \u57fa\u672c\u8bed\u6cd5\u8bf4\u660e\n\n> 2022-03-26 | 2026-07-01\n> https:\/\/www.modbus.cn\/en\/7374.html\n\n**LUA \u811a\u672c\u6587\u6863, \u89e6\u63a7\u5c4f\u5f00\u53d1\u6587\u6863**\n\n---\n\n\u672c\u7ae0\u8282\u4ecb\u7ecd\u7b80\u8981\u4ecb\u7ecd\u57fa\u672c\u7684lua\u8bed\u6cd5\uff0c\u6765\u81ea[RUNOOB.COM](https:\/\/www.runoob.com\/lua\/lua-basic-syntax.html)\u57fa\u7840\u6559\u5b66\uff0c\u5982\u6709\u95ee\u9898\uff0c\u8bf7\u8054\u7cfb\u5904\u7406\n\nLua \u7684\u8bed\u6cd5\u6bd4\u8f83\u7b80\u5355\uff0c\u6bd4\u8f83\u5bb9\u6613\u7406\u89e3\uff0c\u529f\u80fd\u5f3a\u5927\u3002\u6240\u4ee5\uff0c\u7b80\u5355\u7684\u5f52\u7eb3\u4e00\u4e0bLua\u7684\u4e00\u4e9b\u8bed\u6cd5\u89c4\u5219\uff0c\u5e2e\u52a9\u5feb\u901f\u5165\u95e8\n\n## 1 \u6ce8\u91ca\n\n#### 1.1 \u5355\u884c\u6ce8\u91ca\n\n\u5199\u4e00\u4e2a\u7a0b\u5e8f\uff0c\u603b\u662f\u5c11\u4e0d\u4e86\u6ce8\u91ca\u7684\u3002\u5728Lua\u4e2d\uff0c\u5355\u884c\u6ce8\u91ca\u4e2d\uff0c\u8fde\u7eed\u4e24\u4e2a\u51cf\u53f7\"**--**\"\u8868\u793a\u6ce8\u91ca\u7684\u5f00\u59cb\uff0c\u4e00\u76f4\u5ef6\u7eed\u5230\u884c\u672b\u4e3a\u6b62\u3002\u76f8\u5f53\u4e8eC\u3001C++\u8bed\u8a00\u4e2d\u7684\"\/\/\"\uff0c\u5982\u4e0b\u6240\u793a\n\n```\n---------- HTTP POST CHANGE PROJECT START ----------\nfunction on_http_finish_cb(key, value)\n\n    if key=='data' \n    then\n        -- do logical operations, user code\n        bell_cnt = 0\n    end\nend\n```\n\n#### 1.2 \u591a\u884c\u6ce8\u91ca\u4e2d\n\n\u7531\"--[[\"\u8868\u793a\u6ce8\u91ca\u5f00\u59cb\uff0c\u5e76\u4e14\u4e00\u76f4\u5ef6\u7eed\u5230\"--]]\"\u4e3a\u6b62\u3002\u8fd9\u79cd\u6ce8\u91ca\u76f8\u5f53\u4e8eC\u8bed\u8a00\u4e2d\u7684\"\/...\/\"\uff0c\u5982\u4e0b\u6240\u793a\n\n```\n---------- HTTP POST CHANGE PROJECT START ----------\nfunction on_http_finish_cb(key, value)\n    if key=='data' \n    then\n    -- do logical operations, user code\n        bell_cnt = 0\n       --[[ for i = sc_comeState, sc_bellFinsh\n        do\n            set_text(i, 3, '00 : 00')\n        end--]]\n    end\nend\n```\n\n## 2. \u8bed\u53e5\u5757\n\n\u8bed\u53e5\u5757\u5728C\u4e2d\u662f\u7528\"{\"\u548c\"}\"\u62ec\u8d77\u6765\u7684\uff0c\u5728Lua\u4e2d\uff0c\u5b83\u662f\u7528do \u548c end \u62ec\u8d77\u6765\u7684\uff0cend\u8868\u793a\u6700\u8fd1\u4e00\u4e2a\u4ee3\u7801\u5757\u7684\u7ed3\u675f\uff0c\u6bd4\u5982\uff1a\n\n```\nfor i = 0, 10\ndo \n    print(\"Hello\") \nend\n```\n\n\u6216\u8005\u7528then\u548cend\u62ec\u8d77\u6765\n\n```\nif 1 + 1 ==2\nthen \n    print(\"Hello\") \nend\n```\n\n## 3. \u53d8\u91cf\u7c7b\u578b\n\nLua \u662f\u52a8\u6001\u7c7b\u578b\u8bed\u8a00\uff0c\u6ca1\u6709\u7c7b\u578b\u5b9a\u4e49\uff08\u7c7b\u578b\u50cfC\uff0c\u6574\u5f62\u3001\u65e0\u7b26\u53f7\u3001\u5b57\u7b26\u7b49\u7b49\uff09,\u53ea\u9700\u8981\u4e3a\u53d8\u91cf\u8d4b\u503c\u3002 \u503c\u53ef\u4ee5\u5b58\u50a8\u5728\u53d8\u91cf\u4e2d\uff0c\u4f5c\u4e3a\u53c2\u6570\u4f20\u9012\u6216\u7ed3\u679c\u8fd4\u56de\u3002Lua \u4e2d\u6709 8 \u4e2a\u57fa\u672c\u7c7b\u578b\u5206\u522b\u4e3a\uff1anil\u3001boolean\u3001number\u3001string\u3001userdata\u3001function\u3001thread \u548c table\uff0c\u5b9e\u9645\u5c4f\u5e55\u5e38\u7528\u7c7b\u578b\u4e3b\u8981\u6709\u4ee5\u4e0b\u51e0\u79cd\n\n\u7c7b\u578b\u63cf\u8ff0nil\u8fd9\u4e2a\u6700\u7b80\u5355\uff0c\u53ea\u6709\u503cnil\u5c5e\u4e8e\u8be5\u7c7b\uff0c\u8868\u793a\u4e00\u4e2a\u65e0\u6548\u503c\uff08\u5728\u6761\u4ef6\u8868\u8fbe\u5f0f\u4e2d\u76f8\u5f53\u4e8efalse\uff09\uff0c\u5e94\u7528\u4e2d\u907f\u514d\u51fa\u73b0nil\u503c\uff0c\u9700\u8981\u505a\u975e\u6cd5\u5224\u65adnumber\u5c4f\u5e55\u7684MCU\u4e3a32\u4f4d\uff0c\u5b9e\u9645\u5c4f\u5e55\u5e94\u7528\u4e2d\uff0c\u8d4b\u503c\u7684\u6570\u503c\u76f8\u5f53\u4e0e\u957f\u6574\u5f62\u6216\u5355\u7cbe\u5ea6\u6d6e\u70b9\u578bstring\u5b57\u7b26\u4e32\u7531\u4e00\u5bf9\u53cc\u5f15\u53f7\u6216\u5355\u5f15\u53f7\u6765\u8868\u793atableLua \u4e2d\u7684\u8868\uff08table\uff09\u5176\u5b9e\u662f\u4e00\u4e2a\"\u5173\u8054\u6570\u7ec4\"\uff08associative arrays\uff09\uff0c\u6570\u7ec4\u7684\u7d22\u5f15\u53ef\u4ee5\u662f\u6570\u5b57\u3001\u5b57\u7b26\u4e32\u6216\u8868\u7c7b\u578b\u3002\u5728 Lua \u91cc\uff0ctable \u7684\u521b\u5efa\u662f\u901a\u8fc7\"\u6784\u9020\u8868\u8fbe\u5f0f\"\u6765\u5b8c\u6210\uff0c\u6700\u7b80\u5355\u6784\u9020\u8868\u8fbe\u5f0f\u662f{}\uff0c\u7528\u6765\u521b\u5efa\u4e00\u4e2a\u7a7a\u8868function\u7531 C \u6216 Lua \u7f16\u5199\u7684\u51fd\u6570\n\n#### 3.1 nil\uff08\u7a7a\uff09\n\nnil \u7c7b\u578b\u8868\u793a\u4e00\u79cd\u6ca1\u6709\u4efb\u4f55\u6709\u6548\u503c\uff0c\u5b83\u53ea\u6709\u4e00\u4e2a\u503c -- nil\uff0c\u4f8b\u5982\u6253\u5370\u4e00\u4e2a\u6ca1\u6709\u8d4b\u503c\u7684\u53d8\u91cf\uff0c\u4fbf\u4f1a\u8f93\u51fa\u4e00\u4e2a nil \u503c\uff1a\n\n```\n> print(type(a))\nnil\n>\n```\n\n\u8fb9\u754c\u503c\u5224\u65ad\uff0c\u5728\u5b9e\u9645\u5e94\u7528\u4e2d\uff0c\u5f15\u7528\u7684\u53d8\u91cf\u9700\u8981\u6700\u597d\u8981\u5224\u65ad\u662f\u5426\u4e3a\u7a7a\uff0c\u6216\u9632\u6b62\u4e3a\u7a7a\n\n```\nif type(a) == 'nil'\nthen\n    \u2013-user code\nelse\n    -\u2013user code\nend\n```\n\n#### 3.2 number\uff08\u6570\u5b57\uff09\n\nLua \u9ed8\u8ba4\u53ea\u6709\u4e00\u79cd number \u7c7b\u578b -- double\uff08\u53cc\u7cbe\u5ea6\uff09\uff0c**\u4f46\u662f\u5c4f\u5e55\u7684MCU\u662f32\u4f4d\u5904\u7406\u5668\uff0c\u6240\u4ee5\uff0c\u5728\u5c4f\u5e55\u8fd0\u884c\u4e0b\u4ec5\u652f\u6301\u5355\u7cbe\u5ea6**\n\n\u4ee5\u4e0b\u51e0\u79cd\u5199\u6cd5\u90fd\u88ab\u770b\u4f5c\u662f number \u7c7b\u578b\uff1a\n\n```\nlocal a = 2\nlocal b = 2.2\nlocal c = 0.2\nlocal d = 0.2e-1\n\nprint(type(a))\nprint(type(b))\nprint(type(c))\nprint(type(d))\n```\n\n\u8fd0\u884c\u5b9e\u4f8b\uff0c\u4ee5\u4e0a\u4ee3\u7801\u6267\u884c\u7ed3\u679c\uff1a\n\n```\n>number\n>number\n>number\n>number\n>>number\n>number\n```\n\n#### 3. 3 string\uff08\u5b57\u7b26\u4e32\uff09\n\n\u5b57\u7b26\u4e32\u7531\u4e00\u5bf9\u53cc\u5f15\u53f7\u6216\u5355\u5f15\u53f7\u6765\u8868\u793a\n\n```\nlocal string1 = \"this is string1\"\nlocal string2 = 'this is string2'\n```\n\n#### 3.4 table\uff08\u8868\uff09\n\n\u76f8\u5f53\u4e8eC\u91cc\u9762\u7684\u6570\u7ec4\uff0c\u5728 Lua \u91cc\uff0ctable \u7684\u521b\u5efa\u662f\u901a\u8fc7\"\u6784\u9020\u8868\u8fbe\u5f0f\"\u6765\u5b8c\u6210\uff0c\u6700\u7b80\u5355\u6784\u9020\u8868\u8fbe\u5f0f\u662f{}\uff0c\u7528\u6765\u521b\u5efa\u4e00\u4e2a\u7a7a\u8868\u3002\u4e5f\u53ef\u4ee5\u5728\u8868\u91cc\u6dfb\u52a0\u4e00\u4e9b\u6570\u636e\uff0c\u76f4\u63a5\u521d\u59cb\u5316\u8868\uff0c\u4e0b\u6807\u9ed8\u8ba4\u4ece1\u5f00\u59cb\uff0c\u8f93\u51fa\u6d4b\u8bd5\u5982\u4e0b\u6240\u793a\n\n```\n-- \u521b\u5efa\u4e00\u4e2a\u7a7a\u7684 table\nlocal tbl1 = {}\n-- \u76f4\u63a5\u521d\u59cb\u8868\nlocal tbl2 = {\"apple\", \"pear\", \"orange\", \"grape\"}\nprint(tbl2[0])\nprint(tbl2[1])\n```\n\n\u8fd0\u884c\u5b9e\u4f8b\uff0c\u4ee5\u4e0a\u4ee3\u7801\u6267\u884c\u7ed3\u679c\uff1a\n\n```\n>nil --\u62a5\u9519\n>apple\n```\n\n\u7ed9\u8868\u7684\u4e0b\u68070\u8d4b\u503c\uff0c\u5728\u8f93\u51fa\u624d\u6b63\u5e38\n\n```\n-- \u76f4\u63a5\u521d\u59cb\u8868\nlocal tbl2 = {\"apple\", \"pear\", \"orange\", \"grape\"}\ntbl2[0] = \"banana\"\nprint(tbl2[0])\nprint(tbl2[1])\n```\n\n\u8fd0\u884c\u5b9e\u4f8b\uff0c\u4ee5\u4e0a\u4ee3\u7801\u6267\u884c\u7ed3\u679c\uff1a\n\n```\n>banana\n>apple\n```\n\n#### 3.5 function\uff08\u51fd\u6570\uff09\n\n\u5728 Lua \u4e2d\uff0c\u51fd\u6570\u5b9a\u4e49\u58f0\u660e\u5982\u4e0b\u6240\u793a\uff0c\u5fc5\u987b\u5b9a\u4e49\u5728\u88ab\u8c03\u7528\u8005\u4e0a\u9762\n\n```\n-- function_test.lua \u811a\u672c\u6587\u4ef6\nfunction factorial1(n)\n    if n == 0 \n    then\n        return 1\n    else\n        return n * factorial1(n - 1)\n    end\nend\n\nprint(factorial1(5))\n```\n\n\u8fd0\u884c\u5b9e\u4f8b\uff0c\u4ee5\u4e0a\u4ee3\u7801\u6267\u884c\u7ed3\u679c\uff1a\n\n```\n>120\n\n```\n\n## 4 \u53d8\u91cf\u5b9a\u4e49\n\n\u53d8\u91cf\u5728\u4f7f\u7528\u524d\uff0c\u9700\u8981\u5728\u4ee3\u7801\u4e2d\u8fdb\u884c\u58f0\u660e\uff0c\u5373\u521b\u5efa\u8be5\u53d8\u91cf\uff0c\u53d8\u91cf\u7684\u9ed8\u8ba4\u503c\u5747\u4e3a nil\n\n\u5168\u5c40\u53d8\u91cf\uff1aLua \u4e2d\u7684\u53d8\u91cf\u5168\u662f\u5168\u5c40\u53d8\u91cf\uff0c\u90a3\u6015\u662f\u8bed\u53e5\u5757\u6216\u662f\u51fd\u6570\u91cc\uff0c\u9664\u975e\u7528 local \u663e\u5f0f\u58f0\u660e\u4e3a\u5c40\u90e8\u53d8\u91cf\n\n\u5c40\u90e8\u53d8\u91cf\uff1a\u4f5c\u7528\u57df\u4e3a\u4ece\u58f0\u660e\u4f4d\u7f6e\u5f00\u59cb\u5230\u6240\u5728\u8bed\u53e5\u5757\u7ed3\u675f\n\n```\n-- test.lua \u6587\u4ef6\u811a\u672c\na = 5               -- \u5168\u5c40\u53d8\u91cf\nlocal b = 5         -- \u5c40\u90e8\u53d8\u91cf\n\nfunction joke()\n    c = 5           -- \u5168\u5c40\u53d8\u91cf\n    local d = 6     -- \u5c40\u90e8\u53d8\u91cf\nend\nprint(c,d)          --> 5 nil\n\ndo\n    local a = 6     -- \u5c40\u90e8\u53d8\u91cf\n    b = 6           -- \u5bf9\u5c40\u90e8\u53d8\u91cf\u91cd\u65b0\u8d4b\u503c\n    print(a,b);     --> 6 6\nend\nprint(a,b)          --> 5 6\n```\n\n## 5 \u63a7\u5236\u8bed\u53e5\n\n#### 5.1 if(\u5224\u8bfb\u8bed\u53e5)\n\n\u63a7\u5236\u7ed3\u6784\u7684\u6761\u4ef6\u8868\u8fbe\u5f0f\u7ed3\u679c\u53ef\u4ee5\u662f\u4efb\u4f55\u503c\uff0cLua\u8ba4\u4e3afalse\u548cnil\u4e3a\u5047\uff0ctrue\u548c\u975enil\u4e3a\u771f\u3002\u8981\u6ce8\u610f\u7684\u662fLua\u4e2d 0 \u4e3a true\uff1a\n\n```\nlocal a = 0\nif a == 0\nthen\n    print(\"a = 0\")\nelseif a > 0 \nthen\n    print(\"a > 0 \")\nelse\n    print(\"a < 0 \")\nend\n```\n\n\u8fd0\u884c\u5b9e\u4f8b\uff0c\u4ee5\u4e0a\u4ee3\u7801\u6267\u884c\u7ed3\u679c\uff1a\n\n```\n>a = 0\n\n```\n\n**\u4e0d\u652f\u6301switch case \u8bed\u53e5**\n\n#### 5.2 while(\u5faa\u73af)\n\n\u5728\u6761\u4ef6\u4e3a true \u65f6\uff0c\u8ba9\u7a0b\u5e8f\u91cd\u590d\u5730\u6267\u884c\u67d0\u4e9b\u8bed\u53e5\u3002\u6267\u884c\u8bed\u53e5\u524d\u4f1a\u5148\u68c0\u67e5\u6761\u4ef6\u662f\u5426\u4e3a true\n\n```\nlocal  a = 10\nwhile(a > 0 )\ndo\n    a = a - 1\nend\n```\n\n#### 5.3 for(\u5faa\u73af)\n\nLua \u7f16\u7a0b\u8bed\u8a00\u4e2d\u6570\u503c for \u5faa\u73af\u8bed\u6cd5\u683c\u5f0f:\n\n- \u6570\u503cfor\u5faa\u73af- \u6cdb\u578bfor\u5faa\u73af\n\n\u6570\u503cfor\u5faa\u73af\n\nLua \u7f16\u7a0b\u8bed\u8a00\u4e2d\u6570\u503c for \u5faa\u73af\u8bed\u6cd5\u683c\u5f0f\uff0cvar \u4ece exp1 \u53d8\u5316\u5230 exp2\uff0c\u6bcf\u6b21\u53d8\u5316\u4ee5 exp3 \u4e3a\u6b65\u957f\u9012\u589e var\uff0c\u5e76\u6267\u884c\u4e00\u6b21 **\"\u6267\u884c\u4f53\"**\u3002exp3 \u662f\u53ef\u9009\u7684\uff0c\u5982\u679c\u4e0d\u6307\u5b9a\uff0c\u9ed8\u8ba4\u4e3a1\u3002\n\n```\nfor var=exp1,exp2,exp3 do  \n    <\u6267\u884c\u4f53>  \nend\n```\n\n\u5b9e\u4f8b\u5faa\u73af\u8f93\u51fa1-5\u6570\u503c:\n\n```\nfor i=1,5 do\n    print(i)\nend\n```\n\n\u8fd0\u884c\u5b9e\u4f8b\uff0c\u4ee5\u4e0a\u4ee3\u7801\u6267\u884c\u7ed3\u679c\uff1a\n\n```\n>1\n>2\n>3\n>4\n>5\n```\n\n\u6cdb\u578bfor\u5faa\u73af\n\n\u6cdb\u578b for \u5faa\u73af\u901a\u8fc7\u4e00\u4e2a\u8fed\u4ee3\u5668\u51fd\u6570\u6765\u904d\u5386\u6240\u6709\u503c\uff0c\u7c7b\u4f3c java \u4e2d\u7684 foreach \u8bed\u53e5\u3002Lua \u7f16\u7a0b\u8bed\u8a00\u4e2d\u6cdb\u578b for \u5faa\u73af\u8bed\u6cd5\u683c\u5f0f\u3002i\u662f\u6570\u7ec4\u7d22\u5f15\u503c\uff0cv\u662f\u5bf9\u5e94\u7d22\u5f15\u7684\u6570\u7ec4\u5143\u7d20\u503c\u3002ipairs\u662fLua\u63d0\u4f9b\u7684\u4e00\u4e2a\u8fed\u4ee3\u5668\u51fd\u6570\uff0c\u7528\u6765\u8fed\u4ee3\u6570\u7ec4\n\n```\n--\u6253\u5370\u6570\u7ec4a\u7684\u6240\u6709\u503c  \na = {\"one\", \"two\", \"three\"}\nfor i, v in ipairs(a) do\n    print(i, v)\nend\n```\n\n\u5b9e\u4f8b\u5faa\u73af\u6570\u7ec4 days\n\n```\ndays = {\"Sunday\",\"Monday\",\"Tuesday\",\"Wednesday\",\"Thursday\",\"Friday\",\"Saturday\"} \nfor i,v in ipairs(days) \ndo \n    print(v) \nend\n```\n\n\u4ee5\u4e0a\u5b9e\u4f8b\u8f93\u51fa\u7ed3\u679c\u4e3a\uff1a\n\n```\n>Sunday\n>Monday\n>Tuesday\n>Wednesday\n>Thursday\n>Friday\n>Saturday\n```\n\n## 6 \u8fd0\u7b97\u7b26\n\n#### 6.1 \u7b97\u672f\u8fd0\u7b97\u7b26\n\n\u4e0b\u8868\u5217\u51fa\u4e86 Lua \u8bed\u8a00\u4e2d\u7684\u5e38\u7528\u7b97\u672f\u8fd0\u7b97\u7b26\uff0c\u8bbe\u5b9a A \u7684\u503c\u4e3a10\uff0cB \u7684\u503c\u4e3a 20\uff1a\n\n\u64cd\u4f5c\u7b26\u63cf\u8ff0\u5b9e\u4f8b+\u52a0\u6cd5A + B \u8f93\u51fa\u7ed3\u679c 30-\u51cf\u6cd5A - B \u8f93\u51fa\u7ed3\u679c -10*\u4e58\u6cd5A * B \u8f93\u51fa\u7ed3\u679c 200\/\u9664\u6cd5B \/ A \u8f93\u51fa\u7ed3\u679c 2%\u53d6\u4f59B % A \u8f93\u51fa\u7ed3\u679c 0^\u4e58\u5e42A^2 \u8f93\u51fa\u7ed3\u679c 100-\u8d1f\u53f7-A \u8f93\u51fa\u7ed3\u679c -10^\u5f02\u5e38\u6216A~B\u7ed3\u679c30&\u4e0eA&B\u7ed3\u679c0I\u6216AIB\u7ed3\u679c30\n\n\u6211\u4eec\u53ef\u4ee5\u901a\u8fc7\u4ee5\u4e0b\u5b9e\u4f8b\u6765\u66f4\u52a0\u900f\u5f7b\u7684\u7406\u89e3\u7b97\u672f\u8fd0\u7b97\u7b26\u7684\u5e94\u7528\uff1a\n\n```\na = 21\nb = 10\n\nc = a + b\nprint(\"Line 1 - c \u7684\u503c\u4e3a \"..c )\n\nc = a - b\nprint(\"Line 2 - c \u7684\u503c\u4e3a \"..c )\n\nc = a * b\nprint(\"Line 3 - c \u7684\u503c\u4e3a \"..c )\n\nc = a \/ b\nprint(\"Line 4 - c \u7684\u503c\u4e3a \"..c )\n\nc = a % b\nprint(\"Line 5 - c \u7684\u503c\u4e3a \"..c )\n\nc = a^2\nprint(\"Line 6 - c \u7684\u503c\u4e3a \"..c )\n\nc = -a\nprint(\"Line 7 - c \u7684\u503c\u4e3a \"..c )\n\nc = a~b\nprint(\"Line 8 - c \u7684\u503c\u4e3a \"..c )\n\nc = a&b\nprint(\"Line 9 - c \u7684\u503c\u4e3a \"..c )\n\nc = a|b\nprint(\"Line 10 - c \u7684\u503c\u4e3a \"..c )\n```\n\n\u4ee5\u4e0a\u7a0b\u5e8f\u6267\u884c\u7ed3\u679c\u4e3a\uff1a\n\n```\n>Line 1 - c \u7684\u503c\u4e3a     31\n>Line 2 - c \u7684\u503c\u4e3a     11\n>Line 3 - c \u7684\u503c\u4e3a     210\n>Line 4 - c \u7684\u503c\u4e3a     2.1\n>Line 5 - c \u7684\u503c\u4e3a     1\n>Line 6 - c \u7684\u503c\u4e3a     441\n>Line 7 - c \u7684\u503c\u4e3a     -21\n>Line 6 - c \u7684\u503c\u4e3a     31\n>Line 7 - c \u7684\u503c\u4e3a     0\n>Line 7 - c \u7684\u503c\u4e3a     31\n```\n\n#### 6.2 \u5173\u7cfb\u8fd0\u7b97\u7b26\n\n\u4e0b\u8868\u5217\u51fa\u4e86 Lua \u8bed\u8a00\u4e2d\u7684\u5e38\u7528\u5173\u7cfb\u8fd0\u7b97\u7b26\uff0c\u8bbe\u5b9a A \u7684\u503c\u4e3a10\uff0cB \u7684\u503c\u4e3a 20\uff1a\n\n\u64cd\u4f5c\u7b26\u63cf\u8ff0\u5b9e\u4f8b==\u7b49\u4e8e\uff0c\u68c0\u6d4b\u4e24\u4e2a\u503c\u662f\u5426\u76f8\u7b49\uff0c\u76f8\u7b49\u8fd4\u56de true\uff0c\u5426\u5219\u8fd4\u56de false(A == B) \u4e3a false\u3002~=\u4e0d\u7b49\u4e8e\uff0c\u68c0\u6d4b\u4e24\u4e2a\u503c\u662f\u5426\u76f8\u7b49\uff0c\u4e0d\u76f8\u7b49\u8fd4\u56de true\uff0c\u5426\u5219\u8fd4\u56de false(A ~= B) \u4e3a true\u3002>\u5927\u4e8e\uff0c\u5982\u679c\u5de6\u8fb9\u7684\u503c\u5927\u4e8e\u53f3\u8fb9\u7684\u503c\uff0c\u8fd4\u56de true\uff0c\u5426\u5219\u8fd4\u56de false(A > B) \u4e3a false\u3002<\u5c0f\u4e8e\uff0c\u5982\u679c\u5de6\u8fb9\u7684\u503c\u5927\u4e8e\u53f3\u8fb9\u7684\u503c\uff0c\u8fd4\u56de false\uff0c\u5426\u5219\u8fd4\u56de true(A < B) \u4e3a true\u3002>=\u5927\u4e8e\u7b49\u4e8e\uff0c\u5982\u679c\u5de6\u8fb9\u7684\u503c\u5927\u4e8e\u7b49\u4e8e\u53f3\u8fb9\u7684\u503c\uff0c\u8fd4\u56de true\uff0c\u5426\u5219\u8fd4\u56de false(A >= B) \u8fd4\u56de false\u3002<=\u5c0f\u4e8e\u7b49\u4e8e\uff0c \u5982\u679c\u5de6\u8fb9\u7684\u503c\u5c0f\u4e8e\u7b49\u4e8e\u53f3\u8fb9\u7684\u503c\uff0c\u8fd4\u56de true\uff0c\u5426\u5219\u8fd4\u56de false(A <= B) \u8fd4\u56de true\u3002\n\n\u5b9e\u4f8b\uff0c\u6211\u4eec\u53ef\u4ee5\u901a\u8fc7\u4ee5\u4e0b\u5b9e\u4f8b\u6765\u66f4\u52a0\u900f\u5f7b\u7684\u7406\u89e3\u5173\u7cfb\u8fd0\u7b97\u7b26\u7684\u5e94\u7528\uff1a\n\n```\na = 21\nb = 10\n\nif( a == b )\nthen\n   print(\"Line 1 - a \u7b49\u4e8e b\" )\nelse\n   print(\"Line 1 - a \u4e0d\u7b49\u4e8e b\" )\nend\n\nif( a ~= b )\nthen\n   print(\"Line 2 - a \u4e0d\u7b49\u4e8e b\" )\nelse\n   print(\"Line 2 - a \u7b49\u4e8e b\" )\nend\n\nif ( a < b )\nthen\n   print(\"Line 3 - a \u5c0f\u4e8e b\" )\nelse\n   print(\"Line 3 - a \u5927\u4e8e\u7b49\u4e8e b\" )\nend\n\nif ( a > b )\nthen\n   print(\"Line 4 - a \u5927\u4e8e b\" )\nelse\n   print(\"Line 5 - a \u5c0f\u4e8e\u7b49\u4e8e b\" )\nend\n\n-- \u4fee\u6539 a \u548c b \u7684\u503c\na = 5\nb = 20\nif ( a <= b )\nthen\n   print(\"Line 5 - a \u5c0f\u4e8e\u7b49\u4e8e  b\" )\nend\n\nif ( b >= a )\nthen\n   print(\"Line 6 - b \u5927\u4e8e\u7b49\u4e8e a\" )\nend\n```\n\n\u4ee5\u4e0a\u7a0b\u5e8f\u6267\u884c\u7ed3\u679c\u4e3a\uff1a\n\n```\n>Line 1 - a \u4e0d\u7b49\u4e8e b\n>Line 2 - a \u4e0d\u7b49\u4e8e b\n>Line 3 - a \u5927\u4e8e\u7b49\u4e8e b\n>Line 4 - a \u5927\u4e8e b\n>Line 5 - a \u5c0f\u4e8e\u7b49\u4e8e  b\n>Line 6 - b \u5927\u4e8e\u7b49\u4e8e a\n```\n\n#### 6.3 \u903b\u8f91\u8fd0\u7b97\u7b26\n\n\u4e0b\u8868\u5217\u51fa\u4e86 Lua \u8bed\u8a00\u4e2d\u7684\u5e38\u7528\u903b\u8f91\u8fd0\u7b97\u7b26\uff0c\u8bbe\u5b9a A \u7684\u503c\u4e3a true\uff0cB \u7684\u503c\u4e3a false\uff1a\n\n\u64cd\u4f5c\u7b26\u63cf\u8ff0\u5b9e\u4f8band\u903b\u8f91\u4e0e\u64cd\u4f5c\u7b26\u3002 \u82e5 A \u4e3a false\uff0c\u5219\u8fd4\u56de A\uff0c\u5426\u5219\u8fd4\u56de B\u3002(A and B) \u4e3a false\u3002or\u903b\u8f91\u6216\u64cd\u4f5c\u7b26\u3002 \u82e5 A \u4e3a true\uff0c\u5219\u8fd4\u56de A\uff0c\u5426\u5219\u8fd4\u56de B\u3002(A or B) \u4e3a true\u3002not\u903b\u8f91\u975e\u64cd\u4f5c\u7b26\u3002\u4e0e\u903b\u8f91\u8fd0\u7b97\u7ed3\u679c\u76f8\u53cd\uff0c\u5982\u679c\u6761\u4ef6\u4e3a true\uff0c\u903b\u8f91\u975e\u4e3a false\u3002not(A and B) \u4e3a true\u3002\n\n\u5b9e\u4f8b\uff0c\u6211\u4eec\u53ef\u4ee5\u901a\u8fc7\u4ee5\u4e0b\u5b9e\u4f8b\u6765\u66f4\u52a0\u900f\u5f7b\u7684\u7406\u89e3\u903b\u8f91\u8fd0\u7b97\u7b26\u7684\u5e94\u7528\uff1a\n\n```\na = true\nb = true\n\nif ( a and b )\nthen\n   print(\"a and b - \u6761\u4ef6\u4e3a true\" )\nend\n\nif ( a or b )\nthen\n   print(\"a or b - \u6761\u4ef6\u4e3a true\" )\nend\n\nprint(\"---------\u5206\u5272\u7ebf---------\" )\n\n-- \u4fee\u6539 a \u548c b \u7684\u503c\na = false\nb = true\n\nif ( a and b )\nthen\n   print(\"a and b - \u6761\u4ef6\u4e3a true\" )\nelse\n   print(\"a and b - \u6761\u4ef6\u4e3a false\" )\nend\n\nif ( not( a and b) )\nthen\n   print(\"not( a and b) - \u6761\u4ef6\u4e3a true\" )\nelse\n   print(\"not( a and b) - \u6761\u4ef6\u4e3a false\" )\nend\n```\n\n\u4ee5\u4e0a\u7a0b\u5e8f\u6267\u884c\u7ed3\u679c\u4e3a\uff1a\n\n```\n>a and b - \u6761\u4ef6\u4e3a true\n>a or b - \u6761\u4ef6\u4e3a true\n>---------\u5206\u5272\u7ebf---------\n>a and b - \u6761\u4ef6\u4e3a false\n>not( a and b) - \u6761\u4ef6\u4e3a true\n```\n\n#### 6.4 \u5176\u4ed6\u8fd0\u7b97\u7b26\n\n\u4e0b\u8868\u5217\u51fa\u4e86 Lua \u8bed\u8a00\u4e2d\u7684\u8fde\u63a5\u8fd0\u7b97\u7b26\u4e0e\u8ba1\u7b97\u8868\u6216\u5b57\u7b26\u4e32\u957f\u5ea6\u7684\u8fd0\u7b97\u7b26\uff1a\n\n\u64cd\u4f5c\u7b26\u63cf\u8ff0\u5b9e\u4f8b..\u8fde\u63a5\u4e24\u4e2a\u5b57\u7b26\u4e32a..b \uff0c\u5176\u4e2d a \u4e3a \"Hello \" \uff0c b \u4e3a \"World\", \u8f93\u51fa\u7ed3\u679c\u4e3a \"Hello World\"\u3002#\u4e00\u5143\u8fd0\u7b97\u7b26\uff0c\u8fd4\u56de\u5b57\u7b26\u4e32\u6216\u8868\u7684\u957f\u5ea6\u3002#\"Hello\" \u8fd4\u56de 5\n\n\u5b9e\u4f8b\uff0c\u6211\u4eec\u53ef\u4ee5\u901a\u8fc7\u4ee5\u4e0b\u5b9e\u4f8b\u6765\u66f4\u52a0\u900f\u5f7b\u7684\u7406\u89e3\u8fde\u63a5\u8fd0\u7b97\u7b26\u4e0e\u8ba1\u7b97\u8868\u6216\u5b57\u7b26\u4e32\u957f\u5ea6\u7684\u8fd0\u7b97\u7b26\u7684\u5e94\u7528\uff1a\n\n```\na = \"Hello \"\nb = \"World\"\n\nprint(\"\u8fde\u63a5\u5b57\u7b26\u4e32 a \u548c b \", a..b )\nprint(\"b \u5b57\u7b26\u4e32\u957f\u5ea6 \",#b )\nprint(\"\u5b57\u7b26\u4e32 Test \u957f\u5ea6 \",#\"Test\" )\nprint(\"\u83dc\u9e1f\u6559\u7a0b\u7f51\u5740\u957f\u5ea6 \",#\"www.runoob.com\" )\n```\n\n\u4ee5\u4e0a\u7a0b\u5e8f\u6267\u884c\u7ed3\u679c\u4e3a\uff1a\n\n```\n>\u8fde\u63a5\u5b57\u7b26\u4e32 a \u548c b     Hello World\n>b \u5b57\u7b26\u4e32\u957f\u5ea6     5\n>\u5b57\u7b26\u4e32 Test \u957f\u5ea6     4\n>\u83dc\u9e1f\u6559\u7a0b\u7f51\u5740\u957f\u5ea6     14\n```\n\n#### 6.5 \u8fd0\u7b97\u7b26\u4f18\u5148\u7ea7\n\n\u4ece\u9ad8\u5230\u4f4e\u7684\u987a\u5e8f\uff1a\n\n```\n^\nnot    - (unary)\n*      \/       %\n+      -\n..\n<      >      <=     >=     ~=     ==\nand\nor\n```\n\n\u9664\u4e86 **^** \u548c **..** \u5916\u6240\u6709\u7684\u4e8c\u5143\u8fd0\u7b97\u7b26\u90fd\u662f\u5de6\u8fde\u63a5\u7684\n\n```\na+i < b\/2+1          <-->       (a+i) < ((b\/2)+1)\n5+x^2*8              <-->       5+((x^2)*8)\na < y and y <= z     <-->       (a < y) and (y <= z)\n-x^2                 <-->       -(x^2)\nx^y^z                <-->       x^(y^z)\n```\n\n\u5b9e\u4f8b\uff0c\u6211\u4eec\u53ef\u4ee5\u901a\u8fc7\u4ee5\u4e0b\u5b9e\u4f8b\u6765\u66f4\u52a0\u900f\u5f7b\u7684\u4e86\u89e3 Lua \u8bed\u8a00\u8fd0\u7b97\u7b26\u7684\u4f18\u5148\u7ea7\uff1a\n\n```\na = 20\nb = 10\nc = 15\nd = 5\n\ne = (a + b) * c \/ d;*-- ( 30 \\* 15 ) \/ 5\nprint(\"(a + b) * c \/ d \u8fd0\u7b97\u503c\u4e3a  :\",e )\n\ne = ((a + b) * c) \/ d; *-- (30 \\* 15 ) \/ 5\nprint(\"((a + b) * c) \/ d \u8fd0\u7b97\u503c\u4e3a :\",e )\n\ne = (a + b) * (c \/ d);*-- (30) \\* (15\/5)\nprint(\"(a + b) * (c \/ d) \u8fd0\u7b97\u503c\u4e3a :\",e )\n\ne = a + (b * c) \/ d; *-- 20 + (150\/5)\nprint(\"a + (b * c) \/ d \u8fd0\u7b97\u503c\u4e3a  :\",e )\n```\n\n\u4ee5\u4e0a\u7a0b\u5e8f\u6267\u884c\u7ed3\u679c\u4e3a\uff1a\n\n```\n>(a + b) * c \/ d \u8fd0\u7b97\u503c\u4e3a  :    90.0\n>((a + b) * c) \/ d \u8fd0\u7b97\u503c\u4e3a :    90.0\n>(a + b) * (c \/ d) \u8fd0\u7b97\u503c\u4e3a :    90.0\n>a + (b * c) \/ d \u8fd0\u7b97\u503c\u4e3a   :    50.0\n```\n\n---\n*modbus.cn*\n"