7.2. Using Simple Patterns To match a pattern (regular expression) against the contents of $_, put the pattern between a pair of forward slashes (/) as we do here: $_ = "yabba dabba doo"; i

  8.2. Option Modifiers Several option modifier letters, sometimes called flags, may be appended as a group right after the ending delimiter of a regular expression to change its behavior from the def

  8.1. Matches with m// We've been writing patterns in pairs of forward slashes, like /fred/. This is a shortcut for the m// (pattern match) operator. As you saw with the qw// operator, you may choose

  8.4. The Binding Operator, =~ Matching against $_ is merely the default; the binding operator (=~) tells Perl to match the pattern on the right against the string on the left, instead of matching ag

  8.3. Anchors By default, if a pattern doesn't match at the start of the string, it can "float" on down the string trying to match somewhere else. But a number of anchors may be used to hold the patt

  8.6. The Match Variables So far, when we've put parentheses into patterns, they've been used only for their ability to group parts of a pattern together. But parentheses also trigger the regular exp

  8.5. Interpolating into Patterns The regular expression is double-quote interpolated as if it were a double-quoted string. This allows us to write a quick grep-like program like this: #!/usr/bin

  8.8. Precedence With all of these metacharacters in regular expressions, you may feel you can't keep track of the players without a scorecard. That's the precedence chart, which shows us which parts

  8.7. General Quantifiers A quantifier in a pattern means to repeat the preceding item a certain number of times. You've seen three quantifiers: *, +, and ?. But if none of those three suits your nee

  9.1. Substitutions with s/// If you think of the m// pattern match as being like your word processor's "search" feature, the "search and replace" feature would be Perl's s/// substitution operator.

  8.9. A Pattern Test Program When in the course of Perl events it becomes necessary for a programmer to write a regular expression, it may be difficult to tell what the pattern will do. It's normal t

  9.4. m// in List Context When you use split, the pattern specifies the separator: the part that isn't the useful data. Sometimes it's easier to specify what you want to keep. When a pattern match (m

  9.3. The join Function The join function doesn't use patterns but performs the opposite function of split: split breaks up a string into a number of pieces, and join glues together a bunch of pieces

  9.2. The split Operator Another operator that uses regular expressions is split, which breaks up a string according to a pattern. This is useful for tab-separated, colon-separated, whitespace-separa

  10.1. The unless Control Structure In an if control structure, the block of code is executed only when the conditional expression is true. If you want to execute a block of code only when the condit

  9.5. More Powerful Regular Expressions After reading (almost) three chapters about regular expressions, you know they're a powerful feature in the core of Perl. The Perl developers have added more f

  10.2. The until Control Structure Sometimes, you'll want to reverse the condition of a while loop. To do that, use until: until ($j > $i) { $j *= 2; } This loop runs until the cond

  10.4. The Naked Block Control Structure The so-called "naked" block is one without a keyword or condition. That is, suppose you start with a while loop, which looks something like this: while (c

  10.3. Expression Modifiers For a more compact notation, an expression may be followed by a modifier that controls it. For example, the if modifier works in a way analogous to an if block: print

  10.5. The elsif Clause Every so often, you may need to check a number of conditional expressions, one after another, to see which one of them is true. This can be done with the if control structure'

  10.6. Autoincrement and Autodecrement You'll often want a scalar variable to count up or down by one. Since these are frequent constructs, there are shortcuts for them like nearly everything else we

柏林噪声(Perlin Noise)(译) 原文链接:http://freespace.virgin.net/hugo.elias/models/m_perlin.htm 翻译:azure Many people have used random number generators in their programs to create unpredictability, make the mot

文件路径可分为：位置、文件、扩展名。以c:/perl/bin/perl.exe來說，位置是指c:/perl/bin，文件名称为perl，扩展名指.exe。 预设情況下，File::Basename假设你用的是Unix型态的路径名称，但可经由呼叫fileparse_set_fstype来改变文档指定，可用的参数包括VMS, MSDOS, MacOS, AmigaOS, MSWin32。 File::

解决办法 下面是前面提出来的问题的解决方法，就是关于城市和国家名称的重新格式化。     1   my %table;     2   while (<>;) {     3    chomp;     4     my ($city, $country) = split /, /;     5     $table{$country} = [] unless exists $table{$cou

#!/usr/bin/perl   # Written by Limeng # May 27, 2010 Changsha   use strict; use File::Basename; use warnings; my $error_file = "error.txt"; my $clone_report_file = "clone_report.txt";   my @error; my

仙子注：这篇文章是半年前翻译的，最早贴于公司内部的BBS上，并引起一些争论。Bloom Filters是一种效率较高的内存索引算法，它本身具有矛盾性：一方面能快速测试目标成员是否存在，另一方面又不可避免的具有假命中率。如下文档仅供参考。 由于不知道如何在这里粘贴图片，因此本文中没有包含图片说明，请对照原文档来阅读，原文档在：http://www.perl.com/pub/a/2004/04/08/

在perl中反勾号（``），system和exec都用来执行命令，这篇文章将给我们介绍它们各自的使用方法，联系，以及区别。 一、使用方法 1.       反勾号（``） 首先，我们有命令输入操作符，也叫反勾号操作符，因为它看起来象这样： $info = `finger $user`; 一个用反勾号（技术上叫重音号）引起的字串首先进行变量替换，就象一个双引号引起的字串一样。得到的结果然后被系统当作

% perl -e 'print "Hello, World!/nabc"; print STDERR "Hi/n";' >err.txt 输出到err.txt： Hello, World! abc 而err.txt中没有包含Hi（Hi 仍然输出到屏幕），这只不过是把标准输出导入到了文件。如果要导入标准错误你必须这样：   % perl   -e 'print "Hello, World!/na

你的灯还亮着吗？》一书中写道： 当你为了寻找解决问题的方法而累得筋疲力尽时，不妨向后看看，看看你是不是已经迷路了？你的问题究竟是什么？ 2005.01.29  增补： QUOTE: 节选自 http://wiki.perlchina.org/main/show/brian%27s+Guide+to+Solving+Any+Perl+Problem 当你的程序碰到了问题时，请试着按照下面的思路处理一

#!/usr/bin/perl -w use strict; =head--comment     公司发布的通信录是以excl文件的形式，要导入我的电话中肯定不行拉，电话 需要.vcf文件格式(lephone)，也就是用91手机助手(AD)导入.... 思路： 1.把excle表格中的信息复制出来，保存为csv文件(可以是/t或是,为分隔符都行)，   命名为phone.csv（这样就不用改角本