Question

关于以下字符串：＆＃34;狗是否吃猫，或者你的猫是否吃了老鼠？＆＃34;

我想在Perl中使用 s /// 来替换每次出现的＆＃34; dog＆＃34;用＆＃34; cat＆＃34;，＆＃34; cat＆＃34;与＆＃34;鼠标＆＃34;和＆＃34;鼠标＆＃34;用＆＃34;狗＆＃34;。

结果是：＆＃34;猫吃老鼠，或者老鼠吃狗了吗？＆＃34;

我的问题是，用猫代替狗后，猫会出现两次，但我只想替换原来的猫。

我知道我可以简单地写几个非全局的替换，但我想知道是否有一个单行代码。

ps：当然我想使用正确的复数，例如“老鼠”而不是“老鼠”

Answer 1

您可以使用正则表达式查找所有匹配项和哈希值以查找替换项下面是从散列保持匹配=＆gt;替换映射的键中找到构造正则表达式的脚本。

裸骨“概念证明”版本：

%S=(dog=>'cat',cat=>'mouse'); # hash with match=>replacements mappings
# substitute "dog" and "cat" for values provided by S hash
s/\b(dog|cat)\b/$S{$1}/g;
# OR if if can easily split input string into "words"
#    substitute "words" present in S hash and keep the rest unchanged
s{\b(\S+?)\b}{$S{$1}//$1}g;

精心制作版本，从散列键和测试构建regexp：

#!/usr/bin/perl
use strict;
use warnings;

# %S - hash keeping match=>replacements pairs
my %S = (
  dog  => "cat",
  dogs => "cats",
  cat  => "mouse",
  cats => "mice",
  mouse => "dog",
  mice  => "dogs",
);
my $regex = sprintf '\b(?:%s)\b', join('|',sort keys %S);
$regex = qr($regex);
print "REGEX: ",$regex,"\n"; # print regexp for finding all matches

while( <DATA> ) {
  print "IN:  ",$_; # print string before rewriting
  s/($regex)/$S{$1}/g; # Replace all matches by replacements provided by %S hash
  print "OUT: ",$_; # print string after rewriting
}

# Put your tests strings in lines below __DATA__
__DATA__
Do dogs eat cats, or does your cat eat a mouse?
Does firecat fly?

用每个子串替换替换多个子串

1 个答案: