str2double.m

matlab6.5

function x = str2double(s)
%STR2DOUBLE Convert string to double precision value.
%   X = STR2DOUBLE(S) converts the string S, which should be an
%   ASCII character representation of a real or complex scalar value, 
%   to MATLAB's double representation.  The string may contain digits,
%   a comma (thousands separator), a decimal point, a leading + or - sign,
%   an 'e' preceeding a power of 10 scale factor, and an 'i' for 
%   a complex unit.
%
%   If the string S does not represent a valid scalar value, STR2DOUBLE(S)
%   returns NaN.
%
%   X = STR2DOUBLE(C) converts the strings in the cell array of strings C
%   to double.  The matrix X returned will be the same size as C.
%
%   Examples
%      str2double('123.45e7')
%      str2double('123 + 45i')
%      str2double('3.14159')
%      str2double('2.7i - 3.14')
%      str2double({'2.71' '3.1415'})
%      str2double('1,200.34')
%
%   See also STR2NUM, NUM2STR, HEX2NUM, CHAR.

%   Copyright 1984-2002 The MathWorks, Inc. 
%   $Revision: 1.10 $  $Date: 2002/04/09 00:33:36 $

if ~isempty(s) & ischar(s)
  % Remove any commas so that numbers formatted like 1,200.34 are handled.
  s(s == ',') = [];
  
  s = deblank(s); % Remove trailing nulls and spaces

  % Try to get 123, 123i, 123i + 45, or 123i - 45
  [a,count,errmsg,nextindex] = sscanf(s,'%f %1[ij] %1[+-] %f',4);
  if isempty(errmsg) & nextindex > length(s)
    if count==1
      x = a;
    elseif count==2
      x = a(1)*i;
    elseif count==4
      sign = (a(3)=='+')*2 - 1;
      x = a(1)*i + sign*a(4);
    else
      x = NaN;
    end
    return
  end
  
  % Try to get 123 + 23i or 123 - 23i
  [a,count,errmsg,nextindex] = sscanf(s,'%f %1[+-] %f %1[ij]',4);
  if isempty(errmsg) & nextindex > length(s)
    if count==4
      sign = (a(2)=='+')*2 - 1;
      x = a(1) + sign*a(3)*i;
    else
      x = NaN;
    end
    return
  end

  % Try to get i, i + 45, or i - 45
  [a,count,errmsg,nextindex] = sscanf(s,'%1[ij] %1[+-] %f',3);
  if isempty(errmsg) & nextindex > length(s)
    if count==1
      x = i;
    elseif count==3
      sign = (a(2)=='+')*2 - 1;
      x = i + sign*a(3);
    else
      x = NaN;
    end
    return
  end
  
  % Try to get 123 + i or 123 - i
  [a,count,errmsg,nextindex] = sscanf(s,'%f %1[+-] %1[ij]',3);
  if isempty(errmsg) & nextindex > length(s)
    if count==1
      x = a(1);
    elseif count==3
      sign = (a(2)=='+')*2 - 1;
      x = a(1) + sign*i;
    else
      x = NaN;
    end
    return
  end

  % Try to get -i, -i + 45, or -i - 45
  [a,count,errmsg,nextindex] = sscanf(s,'%1[+-] %1[ij] %1[+-] %f',4);
  if isempty(errmsg) & nextindex > length(s)
    if count==2
      sign = (a(1)=='+')*2 - 1;
      x = sign*i;
    elseif count==4
      sign1 = (a(1)=='+')*2 - 1;
      sign2 = (a(3)=='+')*2 - 1;
      x = sign1*i + sign2*a(4);
    else
      x = NaN;
    end
    return
  end
  
  % Try to get 123 + 23*i or 123 - 23*i
  [a,count,errmsg,nextindex] = sscanf(s,'%f %1[+-] %f %1[*] %1[ij]',5);
  if isempty(errmsg) & nextindex > length(s)
    if count==5
      sign = (a(2)=='+')*2 - 1;
      x = a(1) + sign*a(3)*i;
    else
      x = NaN;
    end
    return
  end

  % Try to get 123*i, 123*i + 45, or 123*i - 45
  [a,count,errmsg,nextindex] = sscanf(s,'%f %1[*] %1[ij] %1[+-] %f',5);
  if isempty(errmsg) & nextindex > length(s)
    if count==1
      x = a;
    elseif count==3
      x = a(1)*i;
    elseif count==5
      sign = (a(4)=='+')*2 - 1;
      x = a(1)*i + sign*a(5);
    else
      x = NaN;
    end
    return
  end

  % Try to get i*123 + 45 or i*123 - 45
  [a,count,errmsg,nextindex] = sscanf(s,'%1[ij] %1[*] %f %1[+-] %f',5);
  if isempty(errmsg) & nextindex > length(s)
    if count==1
      x = i;
    elseif count==3
      x = i*a(3);
    elseif count==5
      sign = (a(4)=='+')*2 - 1;
      x = i*a(3) + sign*a(5);
    else
      x = NaN;
    end
    return
  end
 
  % Try to get -i*123 + 45 or -i*123 - 45
  [a,count,errmsg,nextindex] = sscanf(s,'%1[+-] %1[ij] %1[*] %f %1[+-] %f',6);
  if isempty(errmsg) & nextindex > length(s)
    if count==2
      sign = (a(1)=='+')*2 - 1;
      x = sign*i;
    elseif count==4
      sign = (a(1)=='+')*2 - 1;
      x = sign*i*a(4);
    elseif count==6
      sign1 = (a(1)=='+')*2 - 1;
      sign2 = (a(5)=='+')*2 - 1;
      x = sign1*i*a(4) + sign2*a(6);
    else
      x = NaN;
    end
    return
  end

  % Try to get 123 + i*45 or 123 - i*45
  [a,count,errmsg,nextindex] = sscanf(s,'%f %1[+-] %1[ij] %1[*] %f',5);
  if isempty(errmsg) & nextindex > length(s)
    if count==5
      sign = (a(2)=='+')*2 - 1;
      x = a(1) + sign*i*a(5);
    else
      x = NaN;
    end
    return
  end
   
  x = NaN;
elseif iscellstr(s)
  for k=prod(size(s)):-1:1,
    x(k) = str2double(s{k});
  end
  x = reshape(x,size(s));
else
  x = NaN;
end