>> S = ['s e'  ;'3 4']
S =
s e
3 4
>> X=str2num(S)
X =
     []
>> [X,OK]=str2num(S)
X =
[]       
OK =
0
>> str2num('1+2i')     %由下邊的幾行程序可以看出，空格的使用對輸出結(jié)果有很大的影響
ans =
   1.0000 + 2.0000i
>> str2num('1 + 2i')
ans =
   1.0000 + 2.0000i
>> str2num('1 +2i')
ans =
   1.0000                  0 + 2.0000i
>>