正则表达式处理文本

s/// 替换:

[root@jhoa 2015]# cat b1.pl 
$_="He's out bowling with Barney tonight.";
s/Barney/Fred/;
print "$_ is $_n";

[root@jhoa 2015]# perl b1.pl 
$_ is He's out bowling with Fred tonight.


用/s 来匹配任意字符  默认情况下,点号(.)无法匹配换行符,这对大多数单行匹配的情况是合适的。

. 圆点用于匹配除换行符外的任何单个字符

+ 意味着一个或多个相同的字符



.+  匹配任意单个字符至少一次

.* 所有任意数量字符。与前一字符结合,可不出现字符

-？ ##零个或一个减号

d+  #一个或多个数字

.?  #零个或一个小数点

d*  ##零个或多个数字

S 非空白

s 空白 n t r f

w 英文字母和数字的字符窜


W 非英文字母和数字的字符串


$_="He's out bowling with Fred tonight.";
s/with (w+)/against $1's team/;
print "$_ is $_n";

[root@jhoa 2015]# perl b2.pl 
$_ is He's out bowling against Fred's team tonight.


[root@jhoa 2015]# cat b3.pl 
$_="green scaly dinosaur";
s/(w+) (w+)/$2,$1/;
print "$_ is $_n";


[root@jhoa 2015]# perl b3.pl 
$_ is scaly,green dinosaur



[root@jhoa 2015]# cat b3.pl 
$_="green scaly dinosaur";
#s/(w+) (w+)/$2,$1/;

s/^/huge,/;
print "$_ is $_n";
[root@jhoa 2015]# perl b3.pl 
$_ is huge,green scaly dinosaur

开头加上huge,/g 全局匹配:

[root@jhoa 2015]# cat b4.pl 
$_="home,sweet home!";
s/home/cave/g;
print "$_ is $_n";
[root@jhoa 2015]# perl b4.pl 
$_ is cave,sweet cave!


将多个空格转换为单个空格
[root@jhoa 2015]# cat b5.pl 
$_="input datat may have    extra      whitespace.   ";
s/s+/ /g;
print "$_ is $_n";
[root@jhoa 2015]# perl b5.pl 
$_ is input data may have extra whitespace.



split 函数:

[root@jhoa 2015]# cat b6.pl 
@fileds = split /:/,"abc:def:g:h";
print "@fields is @filedsn";
[root@jhoa 2015]# perl b6.pl 
@fields is abc def g h


join 函数:
[root@jhoa 2015]# cat b7.pl 
my @old = qw/a b c d e f g/;
my @new = join "xx",@old;
foreach (@new){
print "$_ is $_n";
}
[root@jhoa 2015]# perl b7.pl 
$_ is axxbxxcxxdxxexxfxxg





列表上下问的m //

[root@jhoa 2015]# cat c1.pl 
$_ = "Hello there,neighbor!";

if ($_ =~ /(S+) (S+),(S+)/){

print "$1--$2--$3n";
}
[root@jhoa 2015]# perl c1.pl 
Hello--there--neighbor!


非贪婪量词:

（编辑：李大同）

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