<p>没有那么复杂吧。只要了解颜色的取值规律,知道用symvar()函数查找符号表达式的符号变量就行。</p><p>>> syms x y z w<br >>> s=5*x+y+z*w<br > <br >s =<br > <br >5*x + y + w*z<br > <br >>> symvar(s)<br > <br >ans =<br > <br >[ w, x, y, z]<br > <br >>> symvar(s,1)<br > <br >ans =<br > <br >x<br > <br >>> s=5+y+z*w<br > <br >s =<br > <br >y + w*z + 5<br > <br >>> symvar(s,1)<br > <br >ans =<br > <br >y<br > <br >>> s=5+z*w<br > <br >s =<br > <br >w*z + 5<br > <br >>> symvar(s,1)<br > <br >ans =<br > <br >w</p>