在段落中查找匹配的字符串

Question

我有一个包含 LaTeX 数学方程式的 TXT 文件，其中每个内联方程式前后使用单个 $ 分隔符。

我想在一个段落中找到每个等式，并将分隔符替换为 XML 打开和关闭标记....

例如，

以下段落：

This is the beginning of a paragraph $first equation$ ...and here is some text... $second equation$ ...and here is more text... $third equation$ ...and here is yet more text... $fourth equation$

应该变成：

This is the beginning of a paragraph <equation>first equation</equation> ...and here is some text... <equation>second equation</equation> ...and here is more text... <equation>third equation</equation> ...and here is yet more text... <equation>fourth equation</equation>

我已经尝试过如下的 sed 和 perl 命令：

perl -p -e 's/($)(.*[^$])($)/<equation><\/equation>/'

但是这些命令会导致第一个和最后一个方程实例被转换，但是 none 这两个方程之间的方程：

This is the beginning of a paragraph <equation>first equation$ ...and here is some text... $second equation$ ...and here is more text... $third equation$ ...and here is yet more text... $fourth equation</equation>

我还想要一个强大的解决方案，它可以考虑不用作 LaTeX 定界符的单个 $ 的存在。例如，

This is the beginning of a paragraph $first equation$ ...and here is some text that includes a single dollar sign: He paid .50 for a pack of cigarettes... $second equation$ ...and here is more text... $third equation$ ...and here is yet more text... $fourth equation$

不会变成：

This is the beginning of a paragraph <equation>first equation$ ...and here is some text that includes a single dollar sign: He paid <equation>2.50 for a pack of cigarettes... $second equation$ ...and here is more text... $third equation$ ...and here is yet more text... $fourth equation</equation>

注意：我是在Bash.

中写的

Answer 1

注意：本答案的第一部分仅关注替换 $'s 对；对于 OP 的请求 not 替换独立 $'s ...请参阅答案的第二部分。

替换成对的$'s

示例数据：

$ cat latex.txt
... $first equation$ ... $second equation$ ... $third equation$

一个sed想法：

sed -E 's|$([^$]*)$|<equation></equation>|g' latex.txt

其中：

-E - 启用扩展的正则表达式支持
$ - 匹配文字 $
([^$]*) - [捕获组 #1] - 匹配所有非文字 $ 的内容（在本例中为 $'s 对之间的所有内容）
$ - 匹配文字 $
<equation></equation> - 将匹配的字符串替换为 <equation> + contents of capture group + </equation>
/g - 根据需要经常重复 search/replace

这会生成：

... <equation>first equation</equation> ... <equation>second equation</equation> ... <equation>third equation</equation>

独立处理$

如果独立 $ 可以转义（例如，$），一个想法是让 sed 将其替换为无意义的文字，执行 <equation> / </equation>替换，然后将无意义的文字改回 $.

示例数据：

$ cat latex.txt
... $first equation$ ... $second equation$ ... $third equation$
... $first equation$ ... $3.50 cup of coffee ... $third equation$

原始 sed 解决方案与新的替代品：

sed -E 's|\$|LITDOL|g;s|$([^$]*)$|<equation></equation>|g;s|LITDOL|\$|g' latex.txt

我们将 $ 替换为 LITDOL（LITeral DOLlar），执行我们原来的替换，然后将 LITDOL 切换回 $。

生成：

... <equation>first equation</equation> ... <equation>second equation</equation> ... <equation>third equation</equation>
... <equation>first equation</equation> ... $3.50 cup of coffee ... <equation>third equation</equation>

Answer 2

使用负前瞻试试这个 Perl。

$ cat joseph.txt
This is the beginning of a paragraph $first equation$ ...and here is some text that includes a single dollar sign: He paid .50 for a pack of cigarettes... $second equation$ ...and here is more text... $third equation$ ...and here is yet more text... $fourth equation$
$ perl -p -e 's/($)(?![\d.]+)(.+?)($)/<equation><\/equation>/g' joseph.txt
This is the beginning of a paragraph <equation>first equation</equation> ...and here is some text that includes a single dollar sign: He paid .50 for a pack of cigarettes... <equation>second equation</equation> ...and here is more text... <equation>third equation</equation> ...and here is yet more text... <equation>fourth equation</equation>
$

在段落中查找匹配的字符串

Finding Matching Strings Within Paragraphs

regex

perl

awk

sed