I can't fplot(39)

4 次查看（过去 30 天）
Alessandro Tufano
Alessandro Tufano 2018-11-3
编辑： madhan ravi 2018-11-4
I'm trying to have a plot with a constant line at value y=39. I'm using function fplot() with a constant double as argument. This works for any value (e.g. fplot(38), fplot(40)) except for fplot(39). Anyone has an idea or ad alternative way to get a constant line plot on y=39. Thanks A
The error message while running fplot(39) is the following Error using symvar>isquoted (line 154) Quotes in S are not in pairs.
Error in symvar (line 49) q = isquoted(s);
Error in countvars>symvarMulti (line 17) vars = reshape(symvar(c),1,[]);
Error in countvars>symvarMulti (line 10) vars = cellfun(@symvarMulti, c, 'UniformOutput', false);
Error in countvars (line 5) n = numel(symvarMulti(outer));
Error in fplot>singleFplot (line 225) nvars = countvars(fn);
Error in fplot>@(f)singleFplot(cax,{f},limits,extraOpts,args) (line 193) hObj = cellfun(@(f) singleFplot(cax,{f},limits,extraOpts,args),fn{1},'UniformOutput',false);
Error in fplot>vectorizeFplot (line 193) hObj = cellfun(@(f) singleFplot(cax,{f},limits,extraOpts,args),fn{1},'UniformOutput',false);
Error in fplot (line 163) hObj = vectorizeFplot(cax,fn,limits,extraOpts,args);

请先登录，再回答此问题。

采纳的回答

Star Strider
Star Strider 2018-11-3
The fplot function is interpreting ‘39’ as a single quote, its ASCII equivalent:
chr39 = char(39)
chr39 =
'''
Using an anonymous function plots the lines:
fplot(@(x)39+x-x)
The strange appearance avoids several lines of warning messages that would otherwise result.
  5 个评论
显示 3更早的评论
Steven Lord
Steven Lord 2018-11-3
An addendum to John's addendum: if you're using release R2018b or later you can use yline. yline is in MATLAB, while refline is in Statistics and Machine Learning Toolbox.
madhan ravi
madhan ravi 2018-11-4
编辑：madhan ravi 2018-11-4
An addendum to Steven's addendum:
fplot(subs(sym('y'),39)) %does the same
NOTE:
fplot(subs(sym('x'),39)) %won't plot a vertical line
the above will work the same that's why I made a FEX for this purpose

请先登录，再进行评论。

更多回答（0 个）

类别

在 Help Center 和 File Exchange 中查找有关 MATLAB 的更多信息

标签

产品


版本

R2018a

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by