使用 pgfplots 时出现错误栏问题

Question

我是 pgfplots 的新手，但它似乎是一个非常有用的包。不过，我不太明白如何使用误差线。

下面是我的柱形图的代码，其中有些列应该包含误差线。我发现我需要对误差线使用不同的 \addplot 命令，但它们仍然没有显示。

\documentclass{article}
\usepackage{pgfplots}
\pgfplotsset{compat=1.7}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}
\begin{axis}[
    width  = 0.85*\textwidth,
    height = 8cm,
    major x tick style = transparent,
    ybar=2*\pgflinewidth,
    bar width=14pt,
    ymajorgrids = true,
    ylabel = {Concentration [mg/L]},
    symbolic x coords={1,2,3,4},
    xtick = data,
    scaled y ticks = false,
    enlarge x limits=0.25,
    ymin=0,
    legend cell align=left,
    legend style={
            at={(1,-0.40)},
            anchor=south east,
            column sep=1ex
    }
]
    \addplot+[error bars/.cd,,addplot[y dir=both,y explicit]
        coordinates {
        (1, 133.1) 
        (2,251.7) 
        (3,372.4) 
        (4,517.9)
        };

    \addplot+[error bars/.cd,,addplot[y dir=both,y explicit]
         coordinates {
         (1,97.4) +- (0.0, 11.0)
         (2,175.5) +- (0.0, 3.86)
         (3,290.8) +- (0.0, 3.14)
         (4,482.8) +- (0.0, 15.3)
         };

    \addplot+[error bars/.cd,,addplot[y dir=both,y explicit]
         coordinates {
         (1,116.9)
         (2,150.2) +- (0.0, 0.56)
         (3,289.0) +- (0.0, 13.2)
         (4,429.6) +- (0.0, 29.0)
         };

    \legend{Untreated solution,Treated with A,Treated with B}
\end{axis}
\end{tikzpicture}
\end{document}

有人知道为什么这不起作用吗？是不是我的 \begin{axis} 设置中有什么东西阻止它们显示？

提前致谢！

Answer 1

如果我不嵌套addplot，我会得到

\documentclass{article}
\usepackage{pgfplots}
\pgfplotsset{compat=1.7}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}
\begin{axis}[
    width  = 0.85*\textwidth,
    height = 8cm,
    major x tick style = transparent,
    ybar=2*\pgflinewidth,
    bar width=14pt,
    ymajorgrids = true,
    ylabel = {Concentration [mg/L]},
    symbolic x coords={1,2,3,4},
    xtick = data,
    scaled y ticks = false,
    enlarge x limits=0.25,
    ymin=0,
    legend cell align=left,
    legend style={
            at={(1,-0.40)},
            anchor=south east,
            column sep=1ex
    }
]
    \addplot+[error bars/.cd,y dir=both,y explicit]
        coordinates {
        (1, 133.1) 
        (2,251.7) 
        (3,372.4) 
        (4,517.9)
        };

    \addplot+[error bars/.cd,y dir=both,y explicit]
         coordinates {
         (1,97.4) +- (0.0, 11.0)
         (2,175.5) +- (0.0, 3.86)
         (3,290.8) +- (0.0, 3.14)
         (4,482.8) +- (0.0, 15.3)
         };

    \addplot+[error bars/.cd,y dir=both,y explicit]
         coordinates {
         (1,116.9)
         (2,150.2) +- (0.0, 0.56)
         (3,289.0) +- (0.0, 13.2)
         (4,429.6) +- (0.0, 29.0)
         };

    \legend{Untreated solution,Treated with A,Treated with B}
\end{axis}
\end{tikzpicture}
\end{document}

即，误差线会出现+-在数据中的任何地方。