python - pretty print errorbars

since x +- y is not a standard type (it could be seen as a complex with real and imaginary as x and y i guess, but that does not simplify anything...) but you can get full control over the presentation by creating a type and overriding the string function, i.e. something like this

class Res(object):
   def __init__(self, res, delta):
     self.res = res
     self.delta = delta

   def __str__(self):
     return "%f +- %f"%(self.res,self.delta)

if __name__ == '__main__':
   x = Res(0.2710,0.001)
   print(x)
   print(" a result: %s" % x)

you could naturally do something a bit more fancy inside the __str__ function...

For people that are still interested in this question, see the gvar library and here for an example of (at last part of) the desired behavior by the OP.