How to use num2str inside text with latex interpreter?

Hi to everyone, I want to assign a number to a string inside a text command to dynamically change the output of the text inside the plot.

Here is an attempt of coding:

clc;clear all;close all;
figure
i=1

i = 1

plot(1:6,2:7)

text(2,4,'$L_{1}$','Interpreter',"latex");

text(4,5,'$L_{',num2str(i),'}$','Interpreter',"latex");

Error using text
Unrecognized property 1 for class Text.

Can you help me to correclty code the last line?

Answer 1

[Star Strider]

I prefer to use sprintf for this. (If you use any escape characters, you need to use double backslants. See the documentation for detais.).

figure
i=1

i = 1

plot(1:6,2:7)

text(2,4,sprintf('$L_{%d}$',i),'Interpreter',"latex");
text(4,3,sprintf('$L_{\\frac{%d}{2}}$',i),'Interpreter',"latex");

.

[Giuseppe]

Thank you. Can you explain the differences, if they exist, with "num2str"?

[Star Strider]

My pleasure!

I suspect sprintf uses num2str (or something like it) ‘under the hood’. The difference is that sprintf (and its friends) are intended to mix text, various numeric, character, and string variables easily in the same function call, and define their display formats with appropriate formatting.

The sprintf function (and its friends) just make everything easier, the reason I use them.

[Giuseppe]

Clear explaination! Thanks aganin!

[Star Strider]

As always, my pleasure!

Answer 2

[Jeff Miller]

I think you need square brackets like this to assemble all the characters into a single string

text(4,5,['$L_{',num2str(i),'}$'],'Interpreter',"latex");

Answer 3

[dpb]

i=1;
text(0.4,0.5,"L_{" + i + "}")
i=i+1;
text(0.4,0.4,"\it L_{" + i + "}")
i=i+1;
text(0.4,0.3,"\it L\rm_{" + i + "}")

Variations on a theme; the above doesn't require LaTeX; the default TeX interpreter can manage on its own.