Plotting from a Loop - "Error: This statement is incomplete"
显示 更早的评论
I'm trying to plot a tier of my structural array with the following code:
for site = 1:19
plot((eval(sprintf('TVC_ForPointCLM.SMP.Profiles.%.force'))),(eval(sprintf('TVC_ForPointCLM.SMP.Profiles.%.depth_smp'))));
hold on
end
hold off
xlabel('Force (N)')
ylabel ('Distance from SMP initialisation (mm)')
When I run this, I get a message saying "Error: This statement is incomplete." about the 2nd line of the code. I've double checked the parenthesis match, so that's not it, but I'm not sure what else would cause this error.
TVC_ForPointCLM is the structural array, and then there are 19 profiles where % is subsituted into the variable name.
4 个评论
KSSV
2020-4-20
Using eval is a bad idea.....what made you to use eval?
Victoria Dutch
2020-4-20
The more efficient and robust method is to use dynamic fieldnames:
Avoiding eval would help you to debug your code and avoid basic errors in your code.
Victoria Dutch
2020-4-20
采纳的回答
You are still writing the whole thing as a character vector. I don't see any examples in the documentation like that:
Also the dynamic fieldname must be the entire name of a field, not just part of it like you tried. For example:
fnm = sprintf('SMP_%d',site);
TVC_ForPointCLM.SMP.Profiles.(fnm).force
2 个评论
Victoria Dutch
2020-4-20
编辑：Victoria Dutch
2020-4-20
"as I'm trying to plot a field that doesn't exist. "
That is because it doesn't exist.
"when I tried the same principle for the fieldnames SMP_01 ... SMP_09... I get this error"
That isn't the same syntax.
You are (again) trying to use the dynamic fieldname syntax on just part of the fieldname:
.SMP_0(site).
This syntax is interpreted as
.SMP_0(site).
^^^^^ % Fieldname = "SMP_0" (note: not dynamic!).
^^^^^^ % Indexing into an array stored in that field.
And clearly the field SMP_0 does not exist in your structure, thus the error. Compare and note where the parentheses are relative to the period characters (hint: directly adjacent):
.SMP_0(site). % what you tried
.(fnm). % what I gave you and what is shown in the documentation
Exactly as I wrote in my answer, the dynamic fieldname syntax applies only the the entire fieldname, not just part of it as you are trying. That is what the sprintf is for: it lets you define the entire fieldname as a character vector, and then you simply use its output as the entire dynamic fieldname.
fnm = sprintf('SMP_0%d',site);
TVC_ForPointCLM.SMP.Profiles.(fnm).force
Tip: you can easily define a format string which prints two digits and a leading zero when required:
fnm = sprintf('SMP_%02d',site);
then you can use exactly the same code for the different ranges of values, or all of those values in one loop.
更多回答（0 个）
类别
在 帮助中心 和 File Exchange 中查找有关 Loops and Conditional Statements 的更多信息
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!
Translated by 
