垂直偏移茎图

我如何垂直偏移stem图，以使词干从y == 0.5而不是从x轴发出?

How do I vertically offset a stem plot so that the stems emanate from say y == 0.5 instead of from the x-axis?

我知道我可以更改x-tick-marks，但是最好只更改绘图.

I know I could change the x-tick-marks but it would be better to rather just change the plot.

stem(X+0.5)不起作用，因为它会使茎变长.

stem(X+0.5) doesn't work as it will just make the stems longer.

我也有正面和负面的数据.而且我在同一轴上还有其他我不想偏移的图.

Also I have both positive and negative data. And also I have other plots on the same axis which I don't want to offset.

基于下面的路易斯·门多(Luis Mendo)的答案，我为此编写了一个函数(但是实际上，下面的我的答案无论如何都有一个内置的属性):

Based on Luis Mendo's answer below, I have written a function for this (however see my answer below as MATLAB actually has a built-in property for this anyway):

function stem_offset(x_data, y_data, offset, offset_mode, varargin)
%STEM_OFFSET stem plot in which the stems begin at a position vertically
%offset from the x-axis.
%
%   STEM_OFFSET(Y, offset) is the same as stem(Y) but offsets all the lines
%   by the amount in offset
%
%   STEM_OFFSET(X, Y, offset) is the same as stem(X,Y) but offsets all the
%   lines by the amount in offset
%
%   STEM_OFFSET(X, Y, offset, offset_mode) offset_mode is a string
%   specifying if the offset should effect only the base of the stems or
%   also the ends. 'base' for just the base, 'all' for the baseand the
%   ends. 'all' is set by default
%
%   STEM_OFFSET(X, Y, offset, offset_mode, ...) lets call all the stem()
%   options like colour and linewidth etc as you normally would with
%   stem().

    if nargin < 3
        offset = 1:length(y_data);
        y_data = x_data;
    end
    if nargin < 4
        offset_mode = 'all';
    end

    h = stem(x_data, y_data, varargin{:});
    ch = get(h,'Children');

    %Offset the lines
    y_lines = get(ch(1),'YData'); %// this contains y values of the lines

    %Offset the ends
    if strcmp(offset_mode, 'all')
        set(ch(1),'YData',y_lines+offset)
        y_ends = get(ch(2),'YData'); %// this contains y values of the ends
        set(ch(2),'YData',y_ends+offset) 
    else
        set(ch(1),'YData',y_lines+offset*(y_lines==0)) %// replace 0 (i.e. only the start of the lines) by offset
    end

end

我现在已上传到文件交换中心( http ://www.mathworks.com/matlabcentral/fileexchange/45643-stem-plot-with-offset )

Which I have now uploaded to the file exchange (http://www.mathworks.com/matlabcentral/fileexchange/45643-stem-plot-with-offset)