二十五、名企片爬虫面试题 1. 简述一次完整的 http 的通信过程、常用的响应状态码、http 的无状态性、Cookies 等这些概念(2018-5-11-xhq) 一、http 过程 HTTP 通信机制是在一次完整的 HTTP 通信过程中,Web 浏览器与 Web 服务器之间将完成下 列 7 个步骤: 1. 建立 TCP 连接 在 HTTP 工作开始之前,Web 浏览器首先要通过网络与 Web 服务器建立连接,该连接是通过 TCP 来完成的,该协议与 IP 协议共同构建 Internet,即著名的 TCP/IP 协议族,因此 Internet 又被称作是 TCP/IP 网络。HTTP 是比 TCP 更高层次的应用层协议,根据规则,只有低层协议建立之后才能进行更 高层协议的连接,因此,首先要建立 TCP 连接,一般 TCP 连接的端口号是 80。 2. Web 浏览器向 Web 服务器发送请求命令
2023-08-18 16:20:21 8.85MB python 面试宝典 django flask
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vivado的tcl脚本,可用于vivado软件的借鉴参考~方便FPGA开发
2023-03-14 13:20:31 3.27MB 便
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Tcl 语法 Tcl是一种很通用的脚本语言,它几乎在所有的平台上都可以释运行,其强大的功能和简单精妙的语法会使你感到由衷的喜悦,这片文章对 Tcl有很好的描述和说明。极具可读性,我并不是原封不动的翻译而是加上了一些自己的体会和例子,如有错误请指正。如果你看起来很吃力,那是因为 Tcl与一般的语言有一些不同之处,刚开始可能有一些不理解,但很快就会掌握的。请坚持一下,我能坚持写完,你至少也应该坚持读一遍吧!
2023-01-09 09:57:43 98KB Tcl 语法
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VIVADO经常使用TCL脚本对FPGA进行调试,通过JTAG转AXI对内部模块进行控制,但是TCL语言书籍比较少,这边是一个英文的TCL语言学习书籍. 第 1 章. TCL基本知识................................................................................................................1 1.1 什么是TCL..............................................................................................................................1 1.2 TCL自学工具...........................................................................................................................1 1.3 TCL软件包..............................................................................................................................2 1.4 TCL命令格式...........................................................................................................................2 1.5 TCL脚本文件和SOURCE 命令..................................................................................................3 1.6 可执行脚本文件(EXECUTABLE FILE)...........................................................................................3 1.7 获得帮助.................................................................................................................................4 1.7.1 Windows系统.............................................................................................................4 1.7.2 Unix系统......................................................................................................................4 第 2 章. 输出、赋值与替换........................................................................................................5 2.1 PUTS.........................................................................................................................................5 2.2 SET & UNSET..............................................................................................................................5 2.3 替换........................................................................................................................................6 2.3.1 $...................................................................................................................................6 2.3.2 []..................................................................................................................................6 2.3.3 " " 和{}..........................................................................................................................6 2.3.4 \...................................................................................................................................7 第 3 章. 数学表达式与EXPR命令..............................................................................................8 3.1 数学和逻辑运算符..................................................................................................................8 3.2 数学函数.................................................................................................................................8 3.3 数学运算举例.........................................................................................................................9 3.4 INCR命令................................................................................................................................9 第 4 章. 字符串........................................................................................................................10 4.1 基本命令集...........................................................................................................................10 4.2 APPEND命令..........................................................................................................................10 4.3 FORMAT命令..........................................................................................................................10 4.3.1 format命令说明......................................................................................................10 4.3.2 format举例..............................................................................................................11 4.4 SCAN命令.............................................................................................................................12 4.5 BINARY命令...........................................................................................................................13 4.6 SUBST命令..............................................................................................................................14 4.7 STRING 命令...........................................................................................................................15 4.7.1 string 命令列表.........................................................................................................15 4.7.2 字符串比较................................................................................................................16 4.7.3 string match字符串匹配.........................................................................................16 4.7.4 字符串替换................................................................................................................18 4.7.5 字符类别(class)测试.................................................................................................18 4.7.6 字符串映射................................................................................................................19 第 5 章. TCL列表操作..............................................................................................................20 5.1 列表命令集...........................................................................................................................20 5.2 LIST命令.................................................................................................................................20 5.3 CONCAT命令.........................................................................................................................21 5.4 LAPPEND命令........................................................................................................................21 5.5 LLENGTH 命令.........................................................................................................................22 5.6 LINDEX命令............................................................................................................................22 5.7 LRANGE命令..........................................................................................................................22 5.8 LINSERT 和LREPLACE命令........................................................................................................22 5.9 LSEARCH命令.........................................................................................................................23 5.10 LSORT命令.............................................................................................................................24 5.11 JOIN与SPLIT命令...................................................................................................................24 5.12 FOREACH控制结构................................................................................................................27 第 6 章. 数组............................................................................................................................28 6.1 数组的定义与格式................................................................................................................28 6.2 数组变量...............................................................................................................................29 6.3 多维数组...............................................................................................................................29 6.4 数组操作命令.......................................................................................................................30 6.4.1 array get命令.........................................................................................................30 6.4.2 array names命令....................................................................................................30 6.4.3 遍历数组...................................................................................................................31 6.4.4 用数组定义结构........................................................................................................31 第 7 章. 控制结构命令.............................................................................................................32 7.1 IF/ELSE命令............................................................................................................................32 7.2 FOR命令................................................................................................................................33 7.3 WHILE命令.............................................................................................................................33 7.4 BREAK 与 CONTINUE命令........................................................................................................34 7.5 SWITCH命令...........................................................................................................................34 7.6 CATCH 命令...........................................................................................................................35 7.7 ERROR命令............................................................................................................................36 7.8 RETURN 命令...........................................................................................................................37 7.9 EXIT命令................................................................................................................................37 第 8 章. 过程与作用域.............................................................................................................38 8.1 PROC—过程定义命令...........................................................................................................38 8.2 作用域...................................................................................................................................40 8.2.1 过程的作用域............................................................................................................40 8.2.2 变量的作用域............................................................................................................40 8.3 UPVAR命令............................................................................................................................42 8.4 RENAME命令.........................................................................................................................44 8.5 特殊变量...............................................................................................................................45 8.5.1 命令行参数................................................................................................................45 8.5.2 env--环境变量数组...................................................................................................45 8.6 EVAL命令..............................................................................................................................46 8.7 UPLEVEL命令..........................................................................................................................48 第 9 章. 正则表达式(REGULAR EXPRESSIONS)...................................................................49 9.1 REGEXP命令..........................................................................................................................49 9.2 REGSUB命令...........................................................................................................................51 9.3 正则表达式的语法................................................................................................................52 9.3.1 分支(branch)和原子(atom)....................................................................................52 9.3.2 基本语法...................................................................................................................52 9.3.2.1 匹配字符........................................................................................................................................52 9.3.2.2 限定匹配........................................................................................................................................53 9.3.2.3 方括号表达式与字符集.................................................................................................................53 9.3.2.4 匹配分支........................................................................................................................................54 9.3.2.5 量词(Qulifier)...........................................................................................................................54 9.3.2.6 子模式与匹配报告捕获.................................................................................................................55 9.3.2.7 反斜杠引用....................................................................................................................................56 9.3.2.8 匹配优先级....................................................................................................................................56 9.3.3 高级正则表达式(AREs).........................................................................................57 9.3.3.1 反斜杠换码(escape)序列............................................................................................................57 9.3.3.2 归整元素(collating element).....................................................................................................57 9.3.3.3 等价类(equivalence class)........................................................................................................58 9.3.3.4 字符类(character class).............................................................................................................58 9.3.3.5 非贪婪量词....................................................................................................................................59 9.3.3.6 约束量词........................................................................................................................................59 9.3.3.7 回退引用........................................................................................................................................59 9.3.3.8 前瞻(lookahead).........................................................................................................................60 9.3.3.9 换行符敏感的匹配.........................................................................................................................60 9.3.3.10 嵌入式选项...............................................................................................................................60 9.3.3.11 扩展语法...................................................................................................................................60 9.3.4 语法小结...................................................................................................................60 9.3.5 其它支持正则表达式的命令......................................................................................60 第 10 章. 名字空间.................................................................................................................62 10.1 创建名字空间...................................................................................................................62 10.2 用::限定符来使用变量和过程...........................................................................................62 10.3 名字空间的变量...............................................................................................................63 10.4 过程的进口与出口............................................................................................................64 10.5 内省(INTROSPECTION).........................................................................................................65 10.6 名字空间命令集...............................................................................................................65 第 11 章. 跟踪与调试.............................................................................................................67 11.1 CLOCK命令...........................................................................................................................67 11.1.1 clock clicks命令......................................................................................................67 11.1.2 clock seconds命令................................................................................................67 11.1.3 clock format命令...................................................................................................68 11.1.4 clock scan命令.......................................................................................................70 11.2 INFO 命令...............................................................................................................................71 11.2.1 info level..................................................................................................................72 11.2.2 info exists.................................................................................................................72 11.3 TRACE命令............................................................................................................................73 11.3.1 trace variable.........................................................................................................73 11.3.2 trace vdelete..........................................................................................................75 11.3.3 trace vinfo...............................................................................................................75 第 12 章. 脚本库与软件包......................................................................................................76 12.1 声明和使用软件包............................................................................................................76 12.1.1 软件包定位................................................................................................................76 12.1.2 声明软件包命令........................................................................................................76 12.1.3 加载软件包命令........................................................................................................76 12.1.4 自动加载与软件包索引.............................................................................................77 12.1.5 用链接库提供软件包.................................................................................................79 12.2 PACKAGE命令集...................................................................................................................80 12.3 小结..................................................................................................................................80 第 13 章. 文件操作与程序调用...............................................................................................81 13.1 文件操作...........................................................................................................................81 13.1.1 文件I/O....................................................................................................................81 13.1.2 文件系统信息命令.....................................................................................................82 13.1.2.1 glob命令.................................................................................................................................83 13.1.2.2 file命令集.................................................................................................................................83 13.2 程序调用...........................................................................................................................85 13.2.1 用open命令打开一个进程管道..............................................................................85 13.2.2 用exec命令调用程序..............................................................................................87 13.2.3 pid命令....................................................................................................................88 第 14 章. 套接字与事件驱动编程简介....................................................................................89 14.1 套接字编程.......................................................................................................................89 14.1.1 socket命令..............................................................................................................89 14.1.1.1 Client端socket命令..............................................................................................................89 14.1.1.2 Server端socket命令选项......................................................................................................90 14.1.2 用fconfigure配置套接字........................................................................................90 14.1.3 C/S编程举例............................................................................................................90 14.2 事件驱动编程...................................................................................................................93 14.2.1 after命令.................................................................................................................93 14.2.2 fileevent命令..........................................................................................................96 14.2.3 vwait命令................................................................................................................96 14.2.4 fconfigure命令.......................................................................................................97 14.2.4.1 fconfigure语法.......................................................................................................................97 14.2.4.2 非阻塞I/O................................................................................................................................98 14.2.4.3 缓冲..........................................................................................................................................98
2023-01-06 16:54:44 2.43MB TCL VIVADO 脚本
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TCL脚本入门教程.doc
2023-01-05 16:59:00 517KB Tcl Vivado
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FPGA资料 该脚本可以使用运行 将design.sv,fhw.sv,timing.tcl和run_fpga.tcl复制到新文件夹 现在运行quartus_sh -t run_fpga.tcl -project(design_name)-board sockit design_name是不带.sv扩展名的Verilog设计的名称。 Tuples.sv编译为 quartus_sh -t run_fpga.tcl-项目元组-board sockit 还显示使用的资源以获取使用的详细资源,请检查output_files /(设计名称).fit.summary 要获取fmax值,请使用quartus_sta -t Timing.tcl(design_name) 重新编译新的Verilog文件 替换项目中的verilog文件 quartus_sh -t recompile.tcl(设计名称)
2023-01-04 11:40:06 3KB Tcl
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C++编程嵌入Tcl脚本应用程序中经常要进行输入输出重定向处理 网上很难找到完整编程实例,本Demo在tcl8.4.20上调式OK
2022-09-27 17:23:14 1KB C++ Tcl脚本 输入输出 重定向
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推荐,TCL教程(中文)。里面包含了TCL语法,置换(substitution)、变量、表达式、List、控制流、过程(procedure)、字符串操作、文件访问、错误和异常、深入TCL大专题,还有很多细分的专题,推荐使用。
2022-07-23 22:39:47 666KB TCL 脚本语言
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有关tcl脚本语言的使用,各个关键字的使用说明,非常好用 上传重复了,不知道怎么删掉一个? 给大家带了麻烦了
2022-05-26 14:02:57 950KB openssl tcl 代码 实例
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系统学习TCL脚本入门教程 系统学习TCL脚本入门教程 系统学习TCL脚本入门教程 系统学习TCL脚本入门教程 系统学习TCL脚本入门教程
2022-05-02 16:39:58 679KB TCL
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