Basic is complete

Basic/wiki.txt

@@ -137,4 +137,161 @@
     false and false : first is evaluated
     true or true : first is evaluated
     false or true : both are evaluated
-    false or false : both are evaluated
+    false or false : both are evaluated
+
+-> Multiple logical operator in one statement:
+
+    for ex:
+        a < b > c < d
+
+-> is v/s == :
+
+    == : It checks if the value on both side are same. Both
+        side should of same value and type to equate to true.
+
+    is : It check if the location where the value is stored
+        same for both side.
+
+-> Type conversion:
+
+    Some operands cannot be compared because of their incompatible type
+    and even type conversion will also not be allowed as it would make 
+    sence.
+
+    Note: keep in mind what could be compared and what couldn't be.
+
+-> What is a iterable?
+
+    for item in 'Zero to mastery'
+                    ^
+                    |
+                This is a iterable.
+    Anything which can be looped through is a iterable.
+
+    Iterable is an object or a collection which can be iterable over.
+
+    #iterable - list, dictionary, tuple, set, string.
+
+-> To iterate in reverse using for loop:
+
+    for ex:
+        for x in range(10, 0 , -1):   
+
+-> while loop with else:
+
+    for ex:
+
+    while <condition>:
+        ....Statement....
+    else:
+        ....Statement....
+
+    This else part is executed only when the while condition fails.
+
+-> pass keyword:
+
+    pass keyword doesn't do anything. It's just a dummy statement.
+    For example, when we don't what to do inside for loop but still
+    want to run the program without throwing error we can use "pass"
+    keyword to do nothing indicating some other might replace it later.
+    
+-> nested functions:
+
+    User-defined function in python can have function defined inside
+    another function and its scope is limited that function itself.
+
+    for ex:
+        def function1():
+            def function2():
+        
+-> Docstring:
+
+    This can be used inside function to write it as comment
+    and mention what the function can do. It's just like a comment.
+
+    for ex:
+
+        def function():
+            '''
+            What function can do.
+            '''
+
+
+    To print the Docstring. use help(<function-name>) or <fucntion-name>.__doc__
+    which is a dunder function.
+
+-> *args && **kwargs:
+
+    *args : It's just like variable argument in C/C++ (var_arg).
+
+    for ex:
+
+        def fun(*args):
+            print(args)
+
+    -> args : It stores the number of argument as a tuple.
+
+    **kwargs : It stores argument with keywords. It stores it like a 
+                dictionary.
+
+    #Rule: params, *args, default parameters, **kwargs
+            name , *args, i = 'hi'          , **kwargs
+
+-> Walrus operator (:=):
+ 
+    for ex:
+
+    if n := len(a) > 0:
+        ...do something...
+
+    "n = len(a)" is not allowed in python.
+    So, to achieve this we use := operator.
+
+-> Scope in Python:
+
+    Different function have different scope.
+    If and other things use global scope.
+
+
+    Order to check the scope of variable:
+
+    #1 - start with local.
+    #2 - Parent local?
+    #3 - global
+    #4 - built in python functions.
+
+-> global keyword:
+
+    Use this to access global variable in a function scope.
+
+    for ex:
+
+    total = 0
+
+    def count():
+        global total
+        total += 1
+        return 1
+
+
+-> nonlocal keyword:
+
+    This is the very latest feature of feature
+
+    To access the non-local variable which is not present
+    in the local scope of the function but is present in the
+    scope of parent function, in case of nested function.
+
+    for ex:
+
+    def outer():
+        x = "local"
+        def inner():
+            nonlocal x
+            x = "nonlocal"
+            print("inner:", x)
+
+        inner()
+        print("outer:", x)
+
+    outer()