out=StringIsNumber(instr)

function out=StringIsNumber(instr)
% STRINGISNUMBER returns 1 if the input
% string contains only a number
% and otherwise a zero
%
% Created as an example for the thread
% "How to determine if an inputfield
% contains chars or numbers ?"
%
% USAGE:
% >> StringIsNumber('aseeea')
% ans =     0
%
% >> StringIsNumber('123')
% ans =     1
%
% >> StringIsNumber('123.123')
% ans =     1
%
% >> StringIsNumber('a123.123')
% ans =     0
%
% >> StringIsNumber({'123','12.2','a123.123','abc'})
% ans =     1     1     0     0
%
% >> [StringIsNumber('100.') ...
%  StringIsNumber('100.1') ...
%  StringIsNumber('.1') ...
%  StringIsNumber('.') ...
%  StringIsNumber('100') ...
%  StringIsNumber('100a') ...
%  StringIsNumber('dca')]
%  ans = 1 1 1 0 1 0 0
% 
% IT'S NOT FANCY BUT IT WORKS

% Michael Robbins
% [e-mail]
% [e-mail]

temp=regexprep(instr, ... 
  '((\d+\.\d+)|(\d+\.)|(\.\d+)|\d+)','');
if iscellstr(instr)
  out =~cellfun('isempty',instr) ...
     & cellfun('isempty',temp);
else
   out = ~isempty(instr) ...
     &&  isempty(temp); 
end;