ܣȡԪ
ʽSymVectorGetByIndex(f, index)
fű
indexݻ߾

˵
1. indexֵ1fű֮䣬ʼֵΪ1
2.ɹضӦķű

ӣ
f = "12,456,7891,25,12,12,25"; 
a = SymVectorSplit(f,",");
x = [1,2,4];
b = SymVectorGetByIndex(a,x)//سõ½aĵ1,2,4Ԫb
b = 
"12"
"456"
"25"