mirror of
https://github.com/satwikkansal/wtfpython.git
synced 2024-09-11 20:17:08 +03:00
Add example: Not Knot!
Related to https://github.com/satwikkansal/wtfpython/issues/1
This commit is contained in:
parent
39480cc579
commit
6abfb50fc6
29
README.md
vendored
29
README.md
vendored
@ -1451,6 +1451,35 @@ tuple()
|
|||||||
|
|
||||||
---
|
---
|
||||||
|
|
||||||
|
### not knot!
|
||||||
|
|
||||||
|
Suggested by @MostAwesomeDude in [this](https://github.com/satwikkansal/wtfPython/issues/1) issue.
|
||||||
|
|
||||||
|
```py
|
||||||
|
x = True
|
||||||
|
y = False
|
||||||
|
```
|
||||||
|
|
||||||
|
**Output:**
|
||||||
|
```py
|
||||||
|
>>> not x == y
|
||||||
|
True
|
||||||
|
>>> x == not y
|
||||||
|
File "<input>", line 1
|
||||||
|
x == not y
|
||||||
|
^
|
||||||
|
SyntaxError: invalid syntax
|
||||||
|
```
|
||||||
|
|
||||||
|
#### 💡 Explanation:
|
||||||
|
|
||||||
|
* Operator precedence affects how an expression is evaluated, and `==` operator has higher precedence than `not` operator in Python.
|
||||||
|
* So `not x == y` is equivalent to `not (x == y)` which is equivalent to `not (True == False)` finally evaluating to `True`.
|
||||||
|
* But `x == not y` raises a `SyntaxError` because it can be thought of being equivalent to `(x == not) y` and not `x == (not y)` which you might have expected at first sight.
|
||||||
|
* The parser expected the `not` token to be a part of the `not in` operator (because both `==` and `not in` operators have same precedence), but after not being able to find a `in` token following the `not` token, it raises a `SyntaxError`.
|
||||||
|
|
||||||
|
---
|
||||||
|
|
||||||
### Loop variable resilient to changes
|
### Loop variable resilient to changes
|
||||||
|
|
||||||
Suggested by @tukkek in [this](https://github.com/satwikkansal/wtfPython/issues/11) issue.
|
Suggested by @tukkek in [this](https://github.com/satwikkansal/wtfPython/issues/11) issue.
|
||||||
|
Loading…
Reference in New Issue
Block a user