latex命令\label

以前写文章在图和表格中使用\label 加标签便于以后索引，以为只要\label在图片和表格命令中出现就行，没有具体的位置要求，结果显示出来的结果总是不对。今天才发现原来在图片和表格命令中\label的位置是有要求的。

\label {Key}

http://www.ics.uci.edu/~pan/documents/latex/ltx-252.html

 

A \label command appearing in ordinary text assigns to the key the number of the current sectional unit; one appearing inside a numbered environment assigns that number to the key.

A key can consist of any sequence of letters, digits, or punctuation characters. Upper- and lowercase letters are different.

The number assigned to the key can be accessed by use of the \ref command. For example,

\begin{equation} .... .... \label{eq:no1} \end{equation} ... One can see from Eq.~(\ref{eq:no1}) that ...

In a table or figure environment, the \label command should follow the \caption command (or be part of its argument) since it is the \caption command which generates the number.