Update README.md

Signed-off-by: David Rotermund <54365609+davrot@users.noreply.github.com>

Truth_Value_Testing/README.md

@@ -1 +1,79 @@
+# Python -- Truth Value Testing
+
+Questions to [David Rotermund](mailto:davrot@uni-bremen.de)
+
+["Any object can be tested for truth value, for use in an if or while condition or as operand of the Boolean operations below."](https://docs.python.org/3/library/stdtypes.html#truth-value-testing)
+
+# Common mistake to avoid
+For True, False, None we use is and is not for comparisons. They are objects and not values thus we need to use is and is not.
+
+Correct
+```python
+if a: # "a is True" is shortend to "a" due to the official Python style guidelines
+    pass
+
+if a is not True:
+    pass
+
+if a is False:
+    pass
+
+if a is not False:
+    pass
+
+if a is None:
+    pass
+
+if a is not None:
+    pass
+```
+
+Wrong
+```python
+if a == True:
+    pass
+
+if a == False:
+    pass
+
+if a != False:
+    pass
+
+if a != None:
+    pass
+```
+## [Boolean Operations - and, or, not](https://docs.python.org/3/library/stdtypes.html#boolean-operations-and-or-not)
+
+["These are the Boolean operations, ordered by ascending priority:"](https://docs.python.org/3/library/stdtypes.html#boolean-operations-and-or-not)
+
+| | | |
+| ------------- |:-------------:|:-------------:|
+| x or y |	if x is false, then y, else x	| (1) |
+| x or y |	if x is false, then x, else y	| (2) |
+| not x |	if x is false, then True, else False	| (3) |
+
+1. This is a short-circuit operator, so it only evaluates the second argument if the first one is false.
+2. This is a short-circuit operator, so it only evaluates the second argument if the first one is true.
+3. not has a lower priority than non-Boolean operators, so not a == b is interpreted as not (a == b), and a == not b is a syntax error.
+
+## [Comparisons](https://docs.python.org/3/library/stdtypes.html#comparisons)
+
+"There are eight comparison operations in Python. They all have the same priority (which is higher than that of the Boolean operations). Comparisons can be chained arbitrarily; for example, x < y <= z is equivalent to x < y and y <= z, except that y is evaluated only once (but in both cases z is not evaluated at all when x < y is found to be false)."
+
+"This table summarizes the comparison operations:"
+
+| | | | 
+| ------------- |:-------------:|:-------------:|
+| <	| strictly less than	| uses method: __lt__() |
+|<=	| less than or equal |	uses method: __le__() |
+|>	| strictly greater than |	uses method: __gt__() |
+|>=	| greater than or equal |	uses method: __ge__() |
+|==	| equal |	uses method: __eq__() |
+|!=	| not equal	| |
+|is	| object identity |	|
+|is not	| negated object identity	| |
+
+## Resource
+[Built-in Types](https://docs.python.org/3/library/stdtypes.html)
+