def __init__(self, fitshdu, columns):
self.columns = columns<EOL>if isstring(columns) or isinteger(columns):<EOL><INDENT>self.colnums = [fitshdu._extract_colnum(columns)]<EOL>self.is_scalar = True<EOL>self.columns_list = [columns]<EOL><DEDENT>else:<EOL><INDENT>self.colnums = fitshdu._extract_colnums(columns)<EOL>self.is_scalar = False<EOL>self.columns_list = columns<EOL><DEDENT>self.fitshdu = fitshdu<EOL>
Input is the SFile instance and a list of column names.