update string representation

Author: dham

doc/source/3_objects.rst

@@ -476,6 +476,15 @@ We can now observe the difference in the result:
    In [3]: f                                                                                                          
    Out[3]: Polynomial((1, 2, 0, 4, 5))
 
+When using :ref:`f-strings <python:tut-f-strings>`, the :func:`repr` of a an
+object can be inserted instead of the :class:`str` by using the ``!r`` modifier.
+For example, we could just as well have written the method above as:
+
+.. code-block:: python3
+
+  def __repr__(self):
+      return f"{type(self).__name__}({self.coefficients!r})"
+
 .. _object_equality:
 
 Object equality

doc/source/7_inheritance.rst

@@ -191,8 +191,7 @@ minimal characterisation of a group will suffice.
 
         def __repr__(self):
             """Return the canonical string representation of the element."""
-            return f"{type(self).__name__}" \
-                f"({repr(self.group)}, {repr(self.value)})"
+            return f"{type(self).__name__}{self.group, self.value!r}"
 
 
     class CyclicGroup:

example_code/groups.py

@@ -17,6 +17,7 @@ class Element:
     value:
         The value of this entity. Valid values depend on the group.
     """
+
     def __init__(self, group, value):
         group._validate(value)
         self.group = group
@@ -34,8 +35,7 @@ def __str__(self):
 
     def __repr__(self):
         """Return the canonical string representation of the element."""
-        return f"{type(self).__name__}" \
-               f"({repr(self.group), repr(self.value)})"
+        return f"{type(self).__name__}{self.group, self.value!r}"
 
 
 class Group:
@@ -49,6 +49,7 @@ class Group:
         The primary group parameter, such as order or degree. The
         precise meaning of n changes from subclass to subclass.
     """
+
     def __init__(self, n):
         self.n = n
 
@@ -67,6 +68,7 @@ def __repr__(self):
 
 class CyclicGroup(Group):
     """A cyclic group represented by integer addition modulo n."""
+
     symbol = "C"
 
     def _validate(self, value):