如何在Python中使用字典值进行regex替换，其中键是同一字符串中的另一个匹配对象

Question

我的正则表达式需要匹配一个句子中的两个单词，但只需要替换第二个单词。第一个单词实际上是字典的关键字，在那里获取第二个单词的替换词。在PERL中，它看起来像这样：

$sentence = "Tom's boat is blue";
my %mydict = {}; # some key-pair values for name => color
$sentence =~ s/(\S+)'s boat is (\w+)/$1's boat is actually $mydict{$1}/;
print $sentence;

在python中如何做到这一点呢？

Answer 1

如下所示：

>>> sentence = "Tom's boat is blue"
>>> mydict = { 'Tom': 'green' }
>>> import re
>>> re.sub("(\S+)'s boat is (\w+)", lambda m: "{}'s boat is actually {}".format(m.group(1), mydict[m.group(1)]), sentence)
"Tom's boat is actually green"
>>> 

尽管将lambda提取到命名函数会看起来更好。