clc
a=[ '1671 + 28i'
'1671 + 28i'
'1670 + 28i'];
whos a
a=str2num(a)
whos a
>> a=[ '1671 + 28i'
'1671 + 28i'
'1670 + 28i']
a =
1671 + 28i
1671 + 28i
1670 + 28i
>> b=cellstr(a)
b =
'1671 + 28i'
'1671 + 28i'
'1670 + 28i'
>> c=cell2mat(b)
c =
1671 + 28i
1671 + 28i
1670 + 28i