function i = isdigit(str)
%
% ISDIGIT      True for numeric characters (0-9) in a string variable.
%
% USAGE        ISDIGIT(string)
%
% SEE ALSO     FINDDIGIT
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%              Deirdre Byrne: 18 jan 1995

i = ((str == '0') | (str == '1') | (str == '2') | (str == '3') | ...
    (str == '4') | (str == '5') | (str == '6') | (str == '7') | ...
    (str == '8') | (str == '9'));

clear str
