最近在编辑文本的时候用到了EmEditor的一个好用的正则替换功能。
即我想用搜索到内容的一部分来生成另一段文本。
例如客户提供给我一大堆MYSQL的建立主键的脚本，我想改成MSSQL的建立主键的脚本，这里就用到了这个功能。
--替换前：
ALTER TABLE XXXX
ADD PRIMARY KEY PK_XXXX
(
ID ASC
);
--替换后
ALTER TABLE XXXX
ADD CONSTRAINT PK_XXXX PRIMARY KEY CLUSTERED
(
ID ASC
);
--当然直接删掉PK_XXXX也能符合MSSQL的语法,这里仅为了举例子.
这里可以使用
查找：
ADD PRIMARY KEY (.*)
替换为：
ADD CONSTRAINT \1 PRIMARY KEY CLUSTERED
具体规则可以参考EmEditor的正则表达式帮助文档：\1 - \9
Indicates a back reference - a back reference is a reference to a previous sub-expression that has already been matched. The reference is to what the sub-expression matched, not to the expression itself. A back reference consists of the escape character "\" followed by a digit "1" to "9", "\1" refers to the first sub-expression, "\2" to the second etc. For example, "(a)\1" would capture "a" as the first back reference and match any text "aa". Back references can also be used when using the Replace feature under the Search menu. Use regular expressions to locate a text pattern, and the matching text can be replaced by a specified back reference. For example, "(h)(e)" will find "he", and putting "\1" in the Replace With box will replace "he" with "h" whereas "\2\1" will replace "he" with "eh".