Update content.md

satwikkansal · satwikkansal · commit 3806284f78b1 · 2019-06-07T23:59:19.000+05:30
diff --git a/wtfpython-pypi/content.md b/wtfpython-pypi/content.md
@@ -1,9 +1,10 @@
 <p align="center"><img src="/images/logo.png" alt=""></p>
-<h1 align="center"> What the f*ck Python! 🐍 </h1>
-<p align="center"> An interesting collection of surprising snippets and lesser-known Python features.</p>
+<h1 align="center">What the f*ck Python! 🐍</h1>
+<p align="center">An interesting collection of surprising snippets and lesser-known Python features.</p>
 
 [![WTFPL 2.0][license-image]][license-url]
 
+Translations: [Chinese 中文](https://github.com/leisurelicht/wtfpython-cn)
 
 Python, being a beautifully designed high-level and interpreter-based programming language, provides us with many features for the programmer's comfort. But sometimes, the outcomes of a Python snippet may not seem obvious to a regular user at first sight.
 
@@ -13,7 +14,7 @@ While some of the examples you see below may not be WTFs in the truest sense, bu
 
 If you're an experienced Python programmer, you can take it as a challenge to get most of them right in first attempt. You may be already familiar with some of these examples, and I might be able to revive sweet old memories of yours being bitten by these gotchas :sweat_smile:
 
-If you're a returning reader, you can learn about the new modifications [here](https://github.com/satwikkansal/wtfpython/releases/).
+PS: If you're a returning reader, you can learn about the new modifications [here](https://github.com/satwikkansal/wtfpython/releases/).
 
 So, here we go...
 
@@ -77,7 +78,7 @@ So, here we go...
     - [▶ Yes, it exists!](#-yes-it-exists)
     - [▶ Inpinity *](#-inpinity-)
     - [▶ Mangling time! *](#-mangling-time-)
-  - [Section: Miscallaneous](#section-miscallaneous)
+  - [Section: Miscellaneous](#section-miscellaneous)
     - [▶ `+=` is faster](#--is-faster)
     - [▶ Let's make a giant string!](#-lets-make-a-giant-string)
     - [▶ Explicit typecast of strings](#-explicit-typecast-of-strings)
@@ -97,22 +98,22 @@ All the examples are structured like below:
 
 > ### ▶ Some fancy Title *
 > The asterisk at the end of the title indicates the example was not present in the first release and has been recently added.
-> 
+>
 > ```py
 > # Setting up the code.
 > # Preparation for the magic...
 > ```
-> 
+>
 > **Output (Python version):**
 > ```py
 > >>> triggering_statement
 > Probably unexpected output
 > ```
 > (Optional): One line describing the unexpected output.
-> 
-> 
+>
+>
 > #### 💡 Explanation:
-> 
+>
 > * Brief explanation of what's happening and why is it happening.
 >   ```py
 >   Setting up examples for clarification (if necessary)
@@ -200,10 +201,10 @@ Makes sense, right?
 + In the snippets above, strings are implicitly interned. The decision of when to implicitly intern a string is implementation dependent. There are some facts that can be used to guess if a string will be interned or not:
   * All length 0 and length 1 strings are interned.
   * Strings are interned at compile time (`'wtf'` will be interned but `''.join(['w', 't', 'f']` will not be interned)
-  * Strings that are not composed of ASCII letters, digits or underscores, are not interned. This explains why `'wtf!'` was not interned due to `!`.
+  * Strings that are not composed of ASCII letters, digits or underscores, are not interned. This explains why `'wtf!'` was not interned due to `!`. Cpython implementation of this rule can be found [here](https://github.com/python/cpython/blob/3.6/Objects/codeobject.c#L19)
   <img src="/images/string-intern/string_intern.png" alt="">
 + When `a` and `b` are set to `"wtf!"` in the same line, the Python interpreter creates a new object, then references the second variable at the same time. If you do it on separate lines, it doesn't "know" that there's already `wtf!` as an object (because `"wtf!"` is not implicitly interned as per the facts mentioned above). It's a compiler optimization and specifically applies to the interactive environment.
-+ Constant folding is a technique for [peephole optimization](https://en.wikipedia.org/wiki/Peephole_optimization) in Python. This means the expression `'a'*20` is replaced by `'aaaaaaaaaaaaaaaaaaaa'` during compilation to reduce few clock cycles during runtime. But since the python bytecode generated after compilation is stored in `.pyc` files, the strings greater than length of 20 are discarded for peephole optimization (Why? Imagine the size of `.pyc` file generated as a result of the expression `'a'*10**10`)
++ Constant folding is a technique for [peephole optimization](https://en.wikipedia.org/wiki/Peephole_optimization) in Python. This means the expression `'a'*20` is replaced by `'aaaaaaaaaaaaaaaaaaaa'` during compilation to reduce few clock cycles during runtime. Constant folding only occurs for strings having length less than 20. (Why? Imagine the size of `.pyc` file generated as a result of the expression `'a'*10**10`). [Here's](https://github.com/python/cpython/blob/3.6/Python/peephole.c#L288) the implementation source for the same.
 
 
 ---
@@ -241,7 +242,7 @@ some_dict[5] = "Python"
   True
   ```
   **Note:** Objects with different values may also have same hash (known as hash collision).
-* When the statement `some_dict[5] = "Python"` is executed, the existing value "JavaScript" is overwritten with "Python" because Python recongnizes `5` and `5.0` as the same keys of the dictionary `some_dict`.
+* When the statement `some_dict[5] = "Python"` is executed, the existing value "JavaScript" is overwritten with "Python" because Python recognizes `5` and `5.0` as the same keys of the dictionary `some_dict`.
 * This StackOverflow [answer](https://stackoverflow.com/a/32211042/4354153) explains beautifully the rationale behind it.
 
 ---
@@ -296,16 +297,24 @@ True
 * But why did the `is` operator evaluated to `False`? Let's see with this snippet.
   ```py
   class WTF(object):
-    def __init__(self): print("I ")
-    def __del__(self): print("D ")
+    def __init__(self): print("I")
+    def __del__(self): print("D")
   ```
 
   **Output:**
   ```py
   >>> WTF() is WTF()
-  I I D D
+  I
+  I
+  D
+  D
+  False
   >>> id(WTF()) == id(WTF())
-  I D I D
+  I
+  D
+  I
+  D
+  True
   ```
   As you may observe, the order in which the objects are destroyed is what made all the difference here.
 
@@ -530,7 +539,7 @@ And when the `board` is initialized by multiplying the `row`, this is what happe
 We can avoid this scenario here by not using `row` variable to generate `board`. (Asked in [this](https://github.com/satwikkansal/wtfpython/issues/68) issue).
 
 ```py
->>> board = [(['']*3)*3] # board = = [['']*3 for _ in range(3)]
+>>> board = [['']*3 for _ in range(3)]
 >>> board[0][0] = "X"
 >>> board
 [['X', '', ''], ['', '', ''], ['', '', '']]
@@ -547,7 +556,7 @@ for x in range(7):
     def some_func():
         return x
     funcs.append(some_func)
-    results.append(some_func())
+    results.append(some_func())  # note the function call here
 
 funcs_results = [func() for func in funcs]
 ```
@@ -766,10 +775,10 @@ for item in mixed_list:
 
 **Output:**
 ```py
->>> booleans_found_so_far
-0
 >>> integers_found_so_far
 4
+>>> booleans_found_so_far
+0
 ```
 
 2\.
@@ -830,7 +839,7 @@ class C(A):
     pass
 ```
 
-**Ouptut:**
+**Output:**
 ```py
 >>> A.x, B.x, C.x
 (1, 1, 1)
@@ -1135,7 +1144,7 @@ str
             and type(other) is SomeClass
             and super().__eq__(other)
         )
-    
+
     # When we define a custom __eq__, Python stops automatically inheriting the
     # __hash__ method, so we need to define it as well
     __hash__ = str.__hash__
@@ -1148,7 +1157,7 @@ str
   >>> s = SomeClass('s')
   >>> some_dict[s] = 40
   >>> some_dict
-  {'s': 40}
+  {'s': 40, 's': 42}
   >>> keys = list(some_dict.keys())
   >>> type(keys[0]), type(keys[1])
   (__main__.SomeClass, str)
@@ -1313,7 +1322,7 @@ Shouldn't that be 100?
   > First, tabs are replaced (from left to right) by one to eight spaces such that the total number of characters up to and including the replacement is a multiple of eight <...>
 * So the "tab" at the last line of `square` function is replaced with eight spaces, and it gets into the loop.
 * Python 3 is kind enough to throw an error for such cases automatically.
-    
+
     **Output (Python 3.x):**
     ```py
     TabError: inconsistent use of tabs and spaces in indentation
@@ -1697,7 +1706,7 @@ a += [5, 6, 7, 8]
 
 * The expression `a = a + [5,6,7,8]` generates a new list and sets `a`'s reference to that new list, leaving `b` unchanged.
 
-* The expression `a + =[5,6,7,8]` is actually mapped to an "extend" function that operates on the list such that `a` and `b` still point to the same list that has been modified in-place.
+* The expression `a += [5,6,7,8]` is actually mapped to an "extend" function that operates on the list such that `a` and `b` still point to the same list that has been modified in-place.
 
 ---
 
@@ -1731,7 +1740,7 @@ UnboundLocalError: local variable 'a' referenced before assignment
       a += 1
       return a
   ```
-  
+
   **Output:**
   ```py
   >>> another_func()
@@ -1895,7 +1904,7 @@ Sshh.. It's a super secret.
 #### 💡 Explanation:
 + `antigravity` module is one of the few easter eggs released by Python developers.
 + `import antigravity` opens up a web browser pointing to the [classic XKCD comic](http://xkcd.com/353/) about Python.
-+ Well, there's more to it. There's **another easter egg inside the easter egg**. If look at the [code](https://github.com/python/cpython/blob/master/Lib/antigravity.py#L7-L17), there's a function defined that purports to implement the [XKCD's geohashing algorithm](https://xkcd.com/426/).
++ Well, there's more to it. There's **another easter egg inside the easter egg**. If you look at the [code](https://github.com/python/cpython/blob/master/Lib/antigravity.py#L7-L17), there's a function defined that purports to implement the [XKCD's geohashing algorithm](https://xkcd.com/426/).
 
 ---
 
@@ -2115,7 +2124,7 @@ AttributeError: 'Yo' object has no attribute '__honey'
 True
 ```
 
-Why did `Yo()._Yo__honey` worked? Only Indian readers would understand.
+Why did `Yo()._Yo__honey` work? Only Indian readers would understand.
 
 #### 💡 Explanation:
 
@@ -2127,7 +2136,7 @@ Why did `Yo()._Yo__honey` worked? Only Indian readers would understand.
 
 ---
 
-## Section: Miscallaneous
+## Section: Miscellaneous
 
 
 ### ▶ `+=` is faster
@@ -2272,7 +2281,7 @@ nan
 ### ▶ Minor Ones
 
 * `join()` is a string operation instead of list operation. (sort of counter-intuitive at first usage)
-  
+
   **💡 Explanation:**
   If `join()` is a method on a string then it can operate on any iterable (list, tuple, iterators). If it were a method on a list, it'd have to be implemented separately by every type. Also, it doesn't make much sense to put a string-specific method on a generic `list` object API.
 
@@ -2350,7 +2359,7 @@ The idea and design for this collection were initially inspired by Denys Dovhan'
 * https://stackoverflow.com/questions/530530/python-2-x-gotchas-and-landmines
 * https://stackoverflow.com/questions/1011431/common-pitfalls-in-python
 * https://www.python.org/doc/humor/
-* https://www.satwikkansal.xyz/archives/posts/python/My-Python-archives/
+* https://www.codementor.io/satwikkansal/python-practices-for-efficient-code-performance-memory-and-usability-aze6oiq65
 
 # 🎓 License
 
@@ -2365,12 +2374,12 @@ The idea and design for this collection were initially inspired by Denys Dovhan'
 
 If you have any wtfs, ideas or suggestions, please share.
 
-## Want to share wtfpython with friends?
+## Surprise your geeky pythonist friends?
 
-You can use these quick links for Twitter and Linkedin.
+You can use these quick links to recommend wtfpython to your friends,
 
-[Twitter](https://twitter.com/intent/tweet?url=https://github.com/satwikkansal/wtfpython&hastags=python,wtfpython) | 
-[Linkedin](https://www.linkedin.com/shareArticle?url=https://github.com/satwikkansal&title=What%20the%20f*ck%20Python!&summary=An%20interesting%20collection%20of%20subtle%20and%20tricky%20Python%20snippets.)
+[Twitter](https://twitter.com/intent/tweet?url=https://github.com/satwikkansal/wtfpython&hastags=python,wtfpython)
+ | [Linkedin](https://www.linkedin.com/shareArticle?url=https://github.com/satwikkansal&title=What%20the%20f*ck%20Python!&summary=An%20interesting%20collection%20of%20subtle%20and%20tricky%20Python%20snippets.)
 
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