dyadic.py 文件源码

def __str__(self, printer=None):
        """Printing method. """
        ar = self.args  # just to shorten things
        if len(ar) == 0:
            return str(0)
        ol = []  # output list, to be concatenated to a string
        for i, v in enumerate(ar):
            # if the coef of the dyadic is 1, we skip the 1
            if ar[i][0] == 1:
                ol.append(' + (' + str(ar[i][1]) + '|' + str(ar[i][2]) + ')')
            # if the coef of the dyadic is -1, we skip the 1
            elif ar[i][0] == -1:
                ol.append(' - (' + str(ar[i][1]) + '|' + str(ar[i][2]) + ')')
            # If the coefficient of the dyadic is not 1 or -1,
            # we might wrap it in parentheses, for readability.
            elif ar[i][0] != 0:
                arg_str = VectorStrPrinter().doprint(ar[i][0])
                if isinstance(ar[i][0], Add):
                    arg_str = "(%s)" % arg_str
                if arg_str[0] == '-':
                    arg_str = arg_str[1:]
                    str_start = ' - '
                else:
                    str_start = ' + '
                ol.append(str_start + arg_str + '*(' + str(ar[i][1]) +
                          '|' + str(ar[i][2]) + ')')
        outstr = ''.join(ol)
        if outstr.startswith(' + '):
            outstr = outstr[3:]
        elif outstr.startswith(' '):
            outstr = outstr[1:]
        return outstr