替换文件中匹配的行，但使用Ruby忽略注释掉的行

如何在Ruby中替换文件，但不涉及注释行？更具体地说，我想更改配置文件中的变量。例如：

irb(main):014:0> string = "#replaceme\n\t\s\t\s# replaceme\nreplaceme\n"
=> "#replaceme\n\t \t # replaceme\nreplaceme\n"
irb(main):015:0> puts string.gsub(%r{replaceme}, 'replaced')
#replaced
                 # replaced
replaced
=> nil
irb(main):016:0>

期望输出：

#replaceme
                 # replaceme
replaced

这个怎么样

puts string.gsub(%r{^replaceme}, 'replaced')

---

我不完全理解这个问题。要在每行中查找并替换，不考虑磅符号后面的文本，可以执行以下操作

def replace_em(str, source, replacement)
  str.split(/(\#.*?$)/).
      map { |s| s[0] == '#' ? s : s.gsub(source, replacement) }.
      join
end

str = "It was known that # that dog has fleas, \nbut who'd know that that dog # wouldn't?"
replace_em(str, "that", "the")
  #=> "It was known the # that dog has fleas, \nbut who'd know the the dog # wouldn't?"

str = "#replaceme\n\t\s\t\s# replaceme\nreplaceme\n"
replace_em(str, "replaceme", "replaced")
  #=> "#replaceme\n\t \t # replaceme\nreplaced\n"

对于字符串

str = "It was known that # that dog has fleas, \nbut who'd know that that dog # wouldn't?"
source = "that"
replacement = "the"

步骤如下

a = str.split(/(\#.*?$)/)
  #=> ["It was known that ", "# that dog has fleas, ",
  #    "\nbut who'd know that that dog ", "# wouldn't?"]

请注意，正则表达式的主体必须放在捕获组中，以便用于拆分字符串的文本作为元素包含在结果数组中。看

---

谢谢你。事实上，我需要非常高质量的替代品，在100%的情况下工作。因此，即使是第

行“此处某物替换我#注释”

也应该替换为

“此处某物替换#注释”

，作为一个例子，如果

string=“cat cat#cat\ncat cat”

和

“cat”

被替换为

“dog”

，那么期望的结果是“dog dog dog dog”`？我主要感兴趣的是知道每行是否可以有多个替换。根据您的示例：

dog dog\cat\ncat cat

和

dog

。那么，是否有可能进行正常的替换，但当发现时，忽略该行，但仅从何处开始？这与Linux命令行的工作原理完全相同。它只执行命令，直到到达#。如果这有帮助的话，多个GSUB是可以的。我不明白为什么

“cat cat”

后面的

“\n”

不会更改为

“dog dog”

，因为那一行中没有英镑符号。对不起，我错过了最后一行应该是

“dog dog”

。我已把你的答案标为正确答案。做得好！效果很好。所以这个机制可以修改配置文件，但是注释掉的行不会被触及，因为不需要。这可以用于厨师，木偶和其他。例如，Chef在默认情况下不提供此功能，并且内置的FileEdit存在一些多字节问题，因此此解决方案是Ruby中的通用解决方案。

b = a.map { |s| s[0] == '#' ? s : s.gsub(source, replacement) }
  #=> ["It was known the ", "# that dog has fleas, ",
  #    "\nbut who'd know the the dog ", "# wouldn't?"]
b.join
  #=> "It was known the # that dog has fleas, \nbut who'd know the the dog # wouldn't?"