Order terms in symbolic poly converted to string

1 Ansicht (letzte 30 Tage)
Ethan Duckworth
Ethan Duckworth am 17 Jul. 2024
Kommentiert: Ethan Duckworth am 18 Jul. 2024
Is there a way to control the order of the terms in a symbolic polynomial that has been converted to string?
E.g. the following
syms x
T=taylor(exp(x),order=3);
string(T)
results in
ans = "x + x^2/2 + 1"
and I would rather have it as 1+x+x^2/2 or the reverse order. I'll be putting this in the title of a plot so if there is some other way to automatically get the correct order in the title that would work equally as well.

Akzeptierte Antwort

Liam Ivers
Liam Ivers am 18 Jul. 2024
Bearbeitet: Liam Ivers am 18 Jul. 2024
Use the sympref function to change the display of the symbolic polynomial:
I noticed that the string function does not update with this change(A = "x + x^2/2 + 1"), but it does if you use the latex command (B = '1+x+\frac{x^2}{2}') which may look better for plot headings.
syms x
T=taylor(exp(x),order=3)
sympref('PolynomialDisplayStyle','ascend')
A = string(T)
B = latex(T)
titletext = ("$" + latex(T) + '$')
title(titletext,Interpreter='latex')
  2 Kommentare
Sam Chak
Sam Chak am 18 Jul. 2024
@Ethan Duckworth, Consider trying this "what-you-see-is-what-you-get" direct approach.
sympref("PolynomialDisplayStyle", "ascend");
syms x
T = taylor(exp(x), order=3)
T = 
titletext = ("$" + latex(T) + '$');
fplot(T), grid on
title(titletext, Interpreter='latex')
Ethan Duckworth
Ethan Duckworth am 18 Jul. 2024
Weird that string(T) doesn't preserve the order of the terms, but that latex(T) does!

Melden Sie sich an, um zu kommentieren.

Weitere Antworten (1)

James Tursa
James Tursa am 18 Jul. 2024
Bearbeitet: James Tursa am 18 Jul. 2024
Brute force if you need the string for some reason?
syms x
ex = taylor(exp(x),order=3)
ex = 
[C,T] = coeffs(ex)
C = 
T = 
terms = fliplr(C.*T)
terms = 
n = numel(terms);
s = char(terms(1));
for k=2:n
c = char(terms(k));
if( c(1)=='-' )
s = [s ' - ' c(2:end)];
else
s = [s ' + ' c];
end
end
s
s = '1 + x + x^2/2'
  1 Kommentar
Ethan Duckworth
Ethan Duckworth am 18 Jul. 2024
Wholy cow! That works, but the shorter approach by @Liam Ivers is the one I accepted.

Melden Sie sich an, um zu kommentieren.

Kategorien

Mehr zu Formula Manipulation and Simplification finden Sie in Help Center und File Exchange

Community Treasure Hunt

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

Start Hunting!

Translated by