在段落中查找匹配字符串

Question

我有一个带有LaTeX数学方程的TXT文件，其中在每个内联方程之前和之后使用一个$分隔符。

我希望在一个段落中找到每个方程，并用XML开始和结束标记替换分隔符.

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... $fourth equation$

应成为：

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sed和perl命令，如下所示：

perl -p -e 's/(\$)(.*[^\$])(\$)/<equation>$2<\/equation>/'

但是，这些命令导致第一次和最后一次方程的转换，但这两种方程之间的任何一种方程都没有：

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>

我还想要一个健壮的解决方案，它可以考虑不作为LaTeX分隔符的单个$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 $2.50 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:我是用巴什写的。

Answer 1

注意：这个答案的第一部分只关注替换对$'s；对于OP对的请求，而不是，替换独立的$'s .见答案的下半部分。

$'s的替换对

样本数据：

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

sed的一个想法是：

sed -E 's|\$([^$]*)\$|<equation>\1</equation>|g' latex.txt

其中：

• -E -启用扩展regex support
• \$ -匹配一个文本$
• ([^$]*) -捕获组#1 -匹配所有非文字$ (在本例中，$'s)
• \$对之间的所有内容-匹配文字$
• <equation>\1</equation> -用<equation> + contents of capture group + </equation>
• /g替换匹配的字符串)-根据需要重复搜索/替换

这就产生了：

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

处理独立$的

如果可以转义独立的$ (例如，\$)，一个想法是让sed用一个无意义的文字替换它，执行<equation> / </equation>替换，然后将无意义的文本更改为\$。

样本数据：

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

使用新的替代品的原始sed解决方案：

sed -E 's|\\\$|LITDOL|g;s|\$([^$]*)\$|<equation>\1</equation>|g;s|LITDOL|\\\$|g' latex.txt

将\$替换为LITDOL (LITeral DOLlar)，执行原始的替换，然后将LITDOL切换回\$。

它产生：

... <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

使用负前瞻性来尝试这个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 $2.50 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>$2<\/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 $2.50 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>
$