Getting the error "Missing $ inserted" in LaTeX

Question

I try to write the following in latex:

\begin{itemize}
    \item \textbf{insert(element|text)} inserts the element or text passed at the start of the selection.
    \item \textbf{insert_after(element|text)} inserts the element or text passed at the end of the selection.
    \item \textbf{replace(element|text)} replaces the selection with the passed text/element.
    \item \textbf{delete()} deletes the selected text.
    \item \textbf{annotate(name,value)} annotates the selected text with the passed name and value-pair. This can either be a hidden meta-data about the selection, or can alter the visible appearance.
    \item \textbf{clear_annotation()} removes any annotation for this specific selection.
    \item \textbf{update_element(value)} performs an update of the element at the selection with the passed value.
\end{itemize}

For some reason, I get a bunch of errors. I think there is something with the use of the word "insert". I get errors like "Missing $ inserted", so it seems like the parses tries to fix some "errors" on my parts. Do I need to escape words like "insert", how do I do that?

Answer 1

The "Missing $ inserted" is probably caused by the underscores and bars. These characters in LaTeX have special meaning in math mode (which is delimited by $ characters). Try escaping them; e.g. update\_element instead of update_element.

However, if you're trying to display code, a better solution would be to use the \verb command, which will typeset the text in a monospaced font and will automatically handle underscores and bars correctly (no need to escape them with \).

Answer 2

It's actually the underscores. Use \_ instead, or include the underscore package.

Answer 3

I had this problem too. I solved it by removing the unnecessary blank line between equation tags. This gives the error:

\begin{equation}
P(\underline{\hat{X}} | \underline{Y}) = ...

\end{equation}

while this code compiles succesfully:

\begin{equation}
P(\underline{\hat{X}} | \underline{Y}) = ...
\end{equation}

Answer 4

also, I had this problem but the bib file wouldn't recompile. I removed the problem, which was an underscore in the note field, and compiled the tex file again, but kept getting the same errors. In the end I del'd the compiled bib file (.bbl I think) and it worked fine. I had to escape the _ using a backslash.

Answer 5

I had the same problem - and I have read all these answers, but unfortunately none of them worked for me. Eventually I tried removing this line

%\usepackage[latin1]{inputenc}

and all errors disappeared.

Answer 6

My first guess is that LaTeX chokes on | outside a math environment. Missing $ inserted is usually a symptom of something like that.

Answer 7

You can also get this error if you use special character greek letters like \alpha \beta and so on outside of math mode. After i wrapped them in \(...\) the error was gone.

Answer 8

In my code, when I got the error, I checked the possible source, In a line, I had typed a beginning \[ and an ending \] due to which the error of missing $ appeared though I tried using $ for both the brackets. Removing the brackets or using $[$ instead of $\[$ solved my problem. If you've something like that, try altering.

Answer 9

I think it gives the error because of the underscore symbol.

Note : underscore symbol should not be written directly, you have to write like as \_.

So fix these kind special symbol errors.

Answer 10

I had this symbol _ in the head of one table and the code didn't run, so I had to delete.

Answer 11

My case was similar to Adrian's. It was an incorrectly written online bib source.

I had

 @online{some_pretty_website, 
    title={Pretty Website}, 
    url={https://www.prettywebsite.com/foo_bar.pdf}
 } 

I had to escape the "_" symbol in the url

 @online{some_pretty_website, 
    title={Pretty Website}, 
    url={https://www.prettywebsite.com/foo\_bar.pdf}
 }