@@ -49,9 +49,9 @@
 #   - write to the stream: the portions of the data from the memory (ex: a variable) are transferred to the file
 
 # three basic modes used to open the stream:
-#   - read mode: a stream opened in this mode allows read operations only; trying to write to the stream will cause an exception UnsupportedOperation
-#   - write mode: a stream opened in this mode allows write operations only; attempting to read the stream will cause UnsupportedOperation again
-#   - update mode: a stream opened in this mode allows both writes and reads
+#   - READ mode: a stream opened in this mode allows read operations only; trying to write to the stream will cause an exception UnsupportedOperation
+#   - WRITE mode: a stream opened in this mode allows write operations only; attempting to read the stream will cause UnsupportedOperation again
+#   - UPDATE mode: a stream opened in this mode allows both writes and reads
 
 # The stream behaves almost like a tape recorder
 # ==> read something from a stream? a virtual head moves over the stream according to the number of bytes transferred from the stream
@@ -71,7 +71,7 @@
 
 
 
-#### OPEN()
+#### OPEN(FILE, MODE, ENCODING)
 
 ### to invoke the object (the file)
 
@@ -80,63 +80,65 @@
 
 ### open()
 #   - very first operation performed on the stream
-#   - successful, the function returns a stream object
-#   - otherwise, an exception is raised, ex:FileNotFoundError
+#       - successful ? ==> the function returns a stream object
+#       - otherwise ==> an exception is raised, ex:FileNotFoundError
 
 
-### file = specifies the name of the file to be associated with the stream
+### file 
+# = specifies the name of the file to be associated with the stream
 
 
-### mode = specifies the open mode used for the stream
+### mode 
+# = specifies the open mode used for the stream
 #   - default opening mode is read in text mode
 #   - string filled with a sequence of characters, and each of them has its own special meaning:
 
-## ==> r = open mode: read
+## ==> R = open mode: READ
 #     the stream will be opened in read mode
 #     the file associated with the stream must exist and has to be readable, otherwise exception raised
 
-## ==> w = open mode: write
+## ==> W = open mode: WRITE
 #     the stream will be opened in write mode
 #     the file associated with the stream doesn't need to exist
 #     if it doesn't exist it will be created
 #     if it exists, it will be truncated to the length of zero (erased)
 #     if the creation isn't possible (ex: due to system permissions), exception
 
-## ==>a = open mode: append
-#     the stream will be opened in append mode
-#     the file associated with the stream doesn't need to exist
-#     if it doesn't exist, it will be created
-#     if it exists the virtual recording head will be set at the end of the file, the previous content of the file remains UNTOUCHED !
-
-## ==> r+ = open mode: read and update
-#     the stream will be opened in read and update mode
-#     the file associated with the stream MUST EXIST and has to be WRITEABLE, otherwise exception
-#     both read and write operations are allowed for the stream
-
-## ==> w+ open mode: write and update
-#     the stream will be opened in write and update mode
-#     the file associated with the stream doesn't need to exist
-#     if it doesn't exist, it will be created
-#     the previous content of the file remains UNTOUCHED
-#     both read and write operations are allowed for the stream.
-
-# If there is a letter b at the end of the mode string it means that the stream is to be opened in binary mode
-# If the mode string ends with a letter t the stream is opened in text mode
+## ==> A = open mode: APPEND
+#      the stream will be opened in append mode
+#      the file associated with the stream doesn't need to exist
+#      if it doesn't exist, it will be created
+#      if it exists the virtual recording head will be set at the end of the file, the previous content of the file remains UNTOUCHED !
+
+## ==> R+ = open mode: READ and UPDATE
+#      the stream will be opened in read and update mode
+#      the file associated with the stream MUST EXIST and has to be WRITEABLE, otherwise exception
+#      both read and write operations are allowed for the stream
+
+## ==> W+ open mode: WRITE and UPDATE
+#      the stream will be opened in write and update mode
+#      the file associated with the stream doesn't need to exist
+#      if it doesn't exist, it will be created
+#      the previous content of the file remains UNTOUCHED
+#      both read and write operations are allowed for the stream.
+
+# If there is a letter B at the end of the mode string it means that the stream is to be opened in BINARY mode
+# If the mode string ends with a letter T the stream is opened in TEXT mode
 # TEXT MODE is the DEFAULT behaviour assumed when no binary/text mode specifier is used
 # the successful opening of a file will set the current file position (the virtual reading/writing head) before 
 #   the first byte of the file if the mode is not a and after the last byte of the file if the mode is set to a
 
 ## encoding = specifies the encoding type, ex:UTF-8 when working with text files
 #   - default encoding depends on the platform used
+
 # all the streams are divided into text and binary streams:
 #   - TEXT streams are structured in lines, they contain typographical characters (letters, digits, punctuation, etc),
 #   arranged in rows (lines), as seen with the naked eye when you look at the contents of the file in the editor
-#   - BINARY streams don't contain text but a sequence of bytes of any value, ex: an executable program, an image, 
-#   an audio or a video clip, a database file, etc.
+#   - BINARY streams don't contain text but a sequence of bytes of any value
+#   ex: an executable program, an image, an audio or a video clip, a database file, etc.
 #   Because these files don't contain lines, the reads and writes relate to portions of data of any size. 
 #   Hence the data is read/written byte by byte, or block by block, where the size of the block usually ranges from one to an arbitrarily chosen value
 
-
 # ! In Unix/Linux systems, the line ends are marked by a single character named LF (ASCII code 10) designated in Python programs as \n.
 # Other operating systems, especially these derived from the prehistoric CP/M system (which applies to Windows family systems, too)
 # use a different convention: the end of line is marked by a pair of characters, CR and LF (ASCII codes 13 and 10) which can be encoded as \r\n.
@@ -162,20 +164,21 @@
 # the source code run in a Windows environment will work properly
 
 
+
 ### 3 Exceptions where open() is not needed
-import sys # 3 processes included int he sys module
+import sys # 3 processes included int the SYS MODULE
 
-## ==> sys.stdin = standard input
+## ==> SYS.STDIN = standard input
 # stdin stream is normally associated with the keyboard, pre-open for reading and regarded as the primary data source for the running programs
 # the well-known input() function reads data from stdin by default
 
 
-## ==> sys.stdout = standard output
+## ==> SYS.STDOUT = standard output
 # stdout stream is normally associated with the screen, pre-open for writing, regarded as the primary target for outputting data by the running program
 # the well-known print() function outputs the data to the stdout stream
 
 
-# #==> sys.stderr = standard error output
+# #==> SYS.STDERR = standard error output
 # stderr stream is normally associated with the screen, pre-open for writing, regarded as the primary place 
 #   where the running program should send information on the errors encountered during its work
 
@@ -199,19 +202,19 @@
 except Exception as exc:
     print("Cannot open the file:", exc)
 # ---
-
 ### 1. **Airbyte**
 # - **Ressources en ligne** :
 #   - [Site officiel](https://airbyte.com/) — Documentation, guides d’utilisation.
 #   - [Tutoriel YouTube](https://www.youtube.com/watch?v=H6D3pWwX1JA) — Introduction à Airbyte.
 #   - [Blog Airbyte](https://airbyte.com/blog) — Cas d’usage, nouveautés.
 # - **Ouvrages** : Aucun ouvrage dédié, mais la documentation est très complète.
 # ...
-#etc
+# etc
 # ==> OK
 
 
 
+
 #### CLOSE()
 stream.close()
 # to get rid of the object
@@ -228,6 +231,7 @@
 
 
 
+
 #### DIAGNOSIS
 
 # IOError object is equipped with a property named errno = error number
@@ -286,9 +290,10 @@
 
 
 
+
 #### Gestion de l'erreur
 
-### try/exept + errno
+### try/exept + ERRNO
 # errno fournit des constantes pour représenter différents codes d'erreur
 # Quand une erreur survient lors de l'ouverture d'un fichier, une exception IOError (ou OSError dans Python 3) est levée
 # cette exception possède un attribut errno qui indique le type précis d'erreur
@@ -323,7 +328,7 @@
 # The file doesn't exist.
 
 
-### strerror()
+### STRERROR()
 # comes from the os module 
 # 1 * argument = error number
 # returns a string describing the meaning of the error 
 
@@ -193,22 +193,42 @@ def __init__(self):
 # {'x': 10, 'y': 20}
 
 
-### dir()	# Returns a list of the specified object's properties and methods
-# can be a variable, a module, etc
+### dir()	
+# returns a list of the specified object's properties and methods
+# PARAMETER can be a variable, a module, (), None
+# RETURN can be a list of:
+#   the module's attribute
+#   names of class attributes
+#   names of object attributes
+#   names of the base class attributes
 
+
+# object/class
 class Person:
   name = "John"
   age = 36
   country = "Norway"
 print(dir(Person))
-['__class__', '__delattr__', '__dict__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__gt__', '__hash__', '__init__', '__init_subclass__', '__le__', '__lt__', '__module__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', '__weakref__', 'age', 'country', 'name']
+# ['__class__', '__delattr__', '__dict__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__gt__', '__hash__', '__init__', '__init_subclass__', '__le__', '__lt__', '__module__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', '__weakref__', 'age', 'country', 'name']
 
+# module
 import math
 for name in dir(math):
   print(name, end=" ")
 # __doc__ __loader__ __name__ __package__ __spec__ acos acosh asin asinh atan atan2 atanh cbrt ceil comb copysign cos cosh degrees dist e erf erfc exp exp2 expm1 fabs factorial floor fma fmod frexp fsum gamma gcd hypot inf isclose isfinite isinf isnan isqrt lcm ldexp lgamma log log10 log1p log2 modf nan nextafter perm pi pow prod radians remainder sin sinh sqrt sumprod tan tanh tau trunc ulp
 
 
+# current local
+print(dir())
+# ['__annotations__', '__builtins__', '__cached__', '__doc__', '__file__', '__loader__', '__name__', '__package__', '__spec__']
+
+# None
+print(dir(None))
+# ['__bool__', '__class__', '__delattr__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__getstate__', 
+#  '__gt__', '__hash__', '__init__', '__init_subclass__', '__le__', '__lt__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', 
+#  '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__']
+
+
 ### divmod()	# Returns the quotient and the remainder when argument1 is divided by argument2
 
 x = divmod(5, 2)
 
@@ -38,6 +38,15 @@
 # 2 ==> exécution de la fonction
 
 
+## lambda n'accepte PAS de RETURN
+# Lambda functions are single expressions, and return is not allowed inside them
+
+lambda x, y: return x + y
+
+# Correct way:
+lambda x, y: x + y
+
+
 ## cas d'usage
 
 def print_function(args, fun):
@@ -54,6 +63,19 @@ def poly(x):
 # f(1)=0
 # f(2)=2    
 
+
+## mélande de lambda et de fonction
+
+def f(a, b):
+    return a(b)
+# La fonction f prend deux arguments : a (une fonction) et b (une valeur)
+
+print(f(lambda x: x and True, 1 > 0))   
+# 1er argument a est une lambda : lambda x: x and True == True + True
+# 2ème argument b est 1 > 0, ce qui retourne True
+# True
+
+
 # ==> avec LAMBDA
 # pas besoin de créer la fonction poly() ==> remplacée par lambda x: 2 * x**2 - 4 * x + 2