【Perl】正则表达式元字符
1 simple
print "It matches\n" if "hello world" =~ /world/;
print "It doesn\'t match\n" if "hello world" !~ /word/;
$_ = "hello world";
print "it matches\n" if m{world};
print "it matches\n" if m!world!;
print "it matches\n" if m(world);
print "it matches\n" if m[world];
2 metacharacter
| . | 任意一个字符\n除外 |
| + | 重复>=1次 |
| * | 重复>=0次 |
| ? | 重复<=1次 |
| $ | 行尾 |
| [] | 字符类，匹配其中任意一个 |
| () | 组，在组中^$表行首行尾 |
| \d | [0-9] |
| \D | [^0-9] |
| \s | 空白字符 |
| \S | [^\s] |
| \w | [0-9a-zA-Z] |
| \W | [^\w] |
| \b | 单词边界 |
| //i | case-insensitive |
| //g | 多次匹配，函数pos记录其位置 |
| s/// | replace |
| s///r | 返回替代结果但并不修改原来的值$_或用=~绑定的值 |
| s///e | 指明计算后的结果替代匹配的字符串 |
$x = "cat dog house"; # 3 words
while ($x =~ /(\w+)/g){
print "Word is $1, ends at position ", pos $x, "\n";
}
# reverse all the words in a string $x = "the cat in the hat"; $x =~ s/(\w+)/reverse $1/ge; # $x contains "eht tac ni eht tah" # convert percentage to decimal $x = "A 39% hit rate"; $x =~ s!(\d+)%!$1/100!e; # $x contains "A 0.39 hit rate"
Date: 2011-10-27 22:02:37
HTML generated by org-mode 6.33x in emacs 23
- 上一篇 »linux shell基础
- 下一篇 »javascript正则表达式获取控制