【Perl】正则表达式元字符
1 simpleprint "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;
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^$表行首行尾
\d
\D
[^0-9]
\s
空白字符
\S
[^\s]
\w
\W
[^\w]
\b
单词边界
//i
case-insensitive
//g
多次匹配，函数pos记录其位置
s///
replace
s///r
返回替代结果但并不修改原来的值$_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"
Author: visaya fan <visayafangmail.com or visayafan163.com>
Date: 2011-10-27 22:02:37
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