如何使RMarkdown（.Rmd）表格标题位于顶部

Question

Usually tables have captions at the top.

However, RMarkdown always places the caption at the bottom for pdf_document outputs:

This is strange because in html docs the caption is automatically placed at the top:

How do I make table captions go to the top in the pdf documents also?

Reproducible example (replace pdf_document with html_document to see both) - the contents of my file tables.Rmd:

---
title: "tables"
author: "Robin Lovelace"
date: "09/16/2014"
output: pdf_document
---

text...

Table: This is a table

| id| age|sex | zone|
|--:|---:|:---|----:|
|  1|  59|m   |    2|
|  2|  54|m   |    2|
|  4|  73|f   |    2|

text...

| id| age|sex | zone|
|--:|---:|:---|----:|
|  1|  59|m   |    2|
|  2|  54|m   |    2|
|  4|  73|f   |    2|

Table: This is a table

texts...

Answer 1

This thread can shed some light on the problem you're having . Note that the latest version of pandoc (1.13.2) now places table captions on top in pdf output.

The following examples are with pandoc-1.12.3

Unfortunately the \\usepackage{floatrow} suggestion doesn't work for longtable (the table environment generated by the LaTeX writer for pandoc ), because it is not a float environment.

---
header-includes: 
  - \usepackage{booktabs}
  - \usepackage{longtable}
  - \usepackage{floatrow}
  - \floatsetup[table]{capposition=top}
output: pdf_document
---

| id| age|sex | zone|
|--:|---:|:---|----:|
|  1|  59|m   |    2|
|  2|  54|m   |    2|
|  4|  73|f   |    2|

Table: This is a table

This table produces the following latex:

\begin{longtable}[c]{@{}rrlr@{}}
\toprule\addlinespace
id & age & sex & zone
\\\addlinespace
\midrule\endhead
1 & 59 & m & 2
\\\addlinespace
2 & 54 & m & 2
\\\addlinespace
4 & 73 & f & 2
\\\addlinespace
\bottomrule
\addlinespace
\caption{This is a table}
\end{longtable}

Which makes the table you described -- the caption does not respond to the \\floatsetup in the yaml header).

To place the caption at the top, \\caption{} can be moved. I don't personally know an easy way to force a longtable caption to the top (but I'm not a LaTeX expert).

\begin{longtable}[c]{@{}rrlr@{}}
\caption{This is a table} \\
\toprule\addlinespace
id & age & sex & zone
\\\addlinespace
\midrule\endhead
1 & 59 & m & 2
\\\addlinespace
2 & 54 & m & 2
\\\addlinespace
4 & 73 & f & 2
\\\addlinespace
\bottomrule
\end{longtable}

You can use the xtable package to generate tables that are in a table environment that responds to the \\floatsetup in the preamble (though the package also gives you the option to place the caption at the top).

```{r results = 'asis'}
library(xtable)
# Preset some options for printing your xtables
options(xtable.caption.placement = 'bottom', # notice \floatsetup overrides
        xtable.include.rownames = FALSE,
        xtable.comment = FALSE,
        xtable.booktabs = TRUE)

xtable(
  data.frame(
    id = c(1L, 2L, 4L),
    age = c(59L, 54L, 73L),
    sex = c('m', 'm', 'f'),
    zone = rep(2L, 3)),
  caption = 'This is a table')
```

The caveat to all of this is that all of the raw LaTeX that is fed to pandoc will be removed if you decide to compile to html... bummer.