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--- notes_pythons [2017/12/23 12:27]
gbdivers
+++ notes_pythons [2018/02/06 14:32] (Version actuelle)
gbdivers
@@ Ligne 1: / Ligne 1: @@
 ====== Notes Python ======
-https://www.tutorialspoint.com/python3/index.htm
+Sources :
+  * https://www.tutorialspoint.com/python3/index.htm
+Aller plus loin :
+  * https://medium.com/activewizards-machine-learning-company/top-15-python-libraries-for-data-science-in-in-2017-ab61b4f9b4a7
 ===== Bases =====
@@ Ligne 501: / Ligne 507: @@
 del dict         # delete entire dictionary
+# Built-in Dictionary Functions and Methods
+cmp(dict1, dict2)
+len(dict)
+str(dict)
+type(variable)
+dict.clear()
+dict.copy()
+dict.fromkeys()
+dict.get(key, default=None)
+dict.has_key(key)
+dict.items()
+dict.keys()
+dict.setdefault(key, default = None)
+dict.update(dict2)
+dict.values()
 </code>
+===== Date and time =====
+<code python>
+import time;  # This is required to include time module.
+ticks = time.time()
+print ("Number of ticks since 12:00am, January 1, 1970:", ticks)
+> time.struct_time(tm_year = 2016, tm_mon = 2, tm_mday = 15, tm_hour = 9,
+   tm_min = 29, tm_sec = 2, tm_wday = 0, tm_yday = 46, tm_isdst = 0)
+# Getting current time
+localtime = time.localtime(time.time())
+localtime = time.asctime( time.localtime(time.time()) ) # formatted
+# The time Module
+time.altzone
+time.asctime([tupletime])
+time.clock( )
+time.ctime([secs])
+time.gmtime([secs])
+time.localtime([secs])
+time.mktime(tupletime)
+time.sleep(secs)
+time.strftime(fmt[,tupletime])
+time.strptime(str,fmt = '%a %b %d %H:%M:%S %Y')
+time.time( )
+time.timezone
+time.tzname
+</code>
+<code python>
+import calendar
+cal = calendar.month(2016, 2)
+print ("Here is the calendar:")
+print (cal)
+# affiche:
+Here is the calendar:
+   February 2016
+Mo Tu We Th Fr Sa Su
+  2  3  4  5  6  7
+  9 10 11 12 13 14
+16 17 18 19 20 21
+23 24 25 26 27 28
+# The calendar Module
+calendar.calendar(year,w = 2,l = 1,c = 6)
+calendar.firstweekday( )
+calendar.isleap(year)
+calendar.leapdays(y1,y2)
+calendar.month(year,month,w = 2,l = 1)
+calendar.monthcalendar(year,month)
+calendar.monthrange(year,month)
+calendar.prcal(year,w = 2,l = 1,c = 6)
+calendar.prmonth(year,month,w = 2,l = 1)
+calendar.setfirstweekday(weekday)
+calendar.timegm(tupletime)
+calendar.weekday(year,month,day)
+</code>
+===== Functions =====
+<code python>
+# Syntax
+def functionname( parameters ):
+   "function_docstring"
+   function_suite
+   return [expression]
+# Function definition is here
+def printme( str ):
+   "This prints a passed string into this function"
+   print (str)
+   return
+# Now you can call printme function
+printme("This is first call to the user defined function!")
+printme("Again second call to the same function")
+# All parameters (arguments) in the Python language are passed by reference.
+# Required Arguments
+def printme( str ):
+# Keyword Arguments
+printme( str = "My string")
+# Default Arguments
+def printinfo( name, age = 35 ):
+#Variable-length Arguments
+def functionname([formal_args,] *var_args_tuple ):
+   "function_docstring"
+   function_suite
+   return [expression]
+# Function definition is here
+def printinfo( arg1, *vartuple ):
+   "This prints a variable passed arguments"
+   print ("Output is: ")
+   print (arg1)
+   for var in vartuple:
+      print (var)
+   return
+# Now you can call printinfo function
+printinfo( 10 )
+printinfo( 70, 60, 50 )
+#The return Statement
+def sum( arg1, arg2 ):
+   return total
+total = sum( 10, 20 )
+</code>
+<code python>
+# The Anonymous Functions
+lambda [arg1 [,arg2,.....argn]]:expression
+# Function definition is here
+sum = lambda arg1, arg2: arg1 + arg2
+# Now you can call sum as a function
+print ("Value of total : ", sum( 10, 20 ))
+print ("Value of total : ", sum( 20, 20 ))
+</code>
+===== Modules =====
+<code python>
+# The import Statement
+import module1[, module2[,... moduleN]
+# support.py
+def print_func( par ):
+   print "Hello : ", par
+   return
+#usage
+import support
+support.print_func("Zara")
+</code>
+<code python>
+# The from...import Statement
+from modname import name1[, name2[, ... nameN]]
+# fib.py
+def fib(n): # return Fibonacci series up to n
+   result = []
+   a, b = 0, 1
+   while b < n:
+      result.append(b)
+      a, b = b, a + b
+   return result
+#usage
+from fib import fib
+</code>
+<code python>
+# The from...import * Statement
+from modname import *
+</code>
+<code python>
+# Executing Modules as Scripts
+#!/usr/bin/python3
+# Fibonacci numbers module
+def fib(n): # return Fibonacci series up to n
+   result = []
+   a, b = 0, 1
+   while b < n:
+      result.append(b)
+      a, b = b, a + b
+   return result
+if __name__ == "__main__":
+   f = fib(100)
+   print(f)
+</code>
+the following sequences
+  - The current directory.
+  - If the module is not found, Python then searches each directory in the shell variable PYTHONPATH.
+  - If all else fails, Python checks the default path. On UNIX, this default path is normally /usr/local/lib/python3/.
+The sys.path variable contains the current directory, PYTHONPATH, and the installation-dependent default.
+<code python>
+dir(plugin)
+locals()
+globals()
+reload(plugin)
+</code>
+<code python>
+# Packages in Python
+Phone/Pots.py
+Phone/IsDn.py
+Phone/G3.py
+# Phone/__init__.py
+from Pots import Pots
+from Isdn import Isdn
+from G3 import G3
+# uses
+import Phone
+Phone.Pots()
+Phone.Isdn()
+Phone.G3()
+</code>
+===== Files I/O =====
+<code python>
+#Printing to the Screen
+print ("Python is really a great language,", "isn't it?")
+#The input Function
+x = input("something:")
+</code>
+<code python>
+# The open Function
+file object = open(file_name [, access_mode][, buffering])
+access_mode = r/r+/w/w+/a, b
+# Open a file
+fileObject.close();
+fo = open("foo.txt", "wb")
+print ("Name of the file: ", fo.name)
+print ("Closed or not : ", fo.closed)
+print ("Opening mode : ", fo.mode)
+fo.close()
+# The write() Method
+fileObject.write(string);
+fo = open("foo.txt", "w")
+fo.write( "Python is a great language.\nYeah its great!!\n")
+fo.close()
+# The read() Method
+fileObject.read([count]);
+fo = open("foo.txt", "r+")
+str = fo.read(10)
+print ("Read String is : ", str)
+fo.close()
+# File Positions
+position = fo.tell()
+position = fo.seek(0, 0)
+# Renaming and Deleting Files
+os.rename(current_file_name, new_file_name)
+os.remove(file_name)
+os.mkdir(dir_name)
+os.chdir(dire_name)
+os.getcwd()
+os.rmdir(dir_name)
+</code>
+===== Exceptions Handling =====
+<code python>
+# Standard Exceptions
+Exception # Base class for all exceptions
+StopIteration # Raised when the next() method of an iterator does not point to any object.
+SystemExit # Raised by the sys.exit() function.
+StandardError # Base class for all built-in exceptions except StopIteration and SystemExit.
+ArithmeticError # Base class for all errors that occur for numeric calculation.
+OverflowError # Raised when a calculation exceeds maximum limit for a numeric type.
+FloatingPointError # Raised when a floating point calculation fails.
+ZeroDivisonError # Raised when division or modulo by zero takes place for all numeric types.
+AssertionError # Raised in case of failure of the Assert statement.
+AttributeError # Raised in case of failure of attribute reference or assignment.
+EOFError # Raised when there is no input from either the raw_input() or input() function and
+         # the end of file is reached.
+ImportError # Raised when an import statement fails.
+KeyboardInterrupt # Raised when the user interrupts program execution, usually by pressing Ctrl+c.
+LookupError # Base class for all lookup errors.
+IndexError # Raised when an index is not found in a sequence.
+KeyError # Raised when the specified key is not found in the dictionary.
+NameError # Raised when an identifier is not found in the local or global namespace.
+UnboundLocalError # Raised when trying to access a local variable in a function or method
+                  # but no value has been assigned to it.
+EnvironmentError # Base class for all exceptions that occur outside the Python environment.
+IOError # Raised when an input/ output operation fails, such as the print statement or the
+        # open() function when trying to open a file that does not exist.
+OSError # Raised for operating system-related errors.
+SyntaxError # Raised when there is an error in Python syntax.
+IndentationError # Raised when indentation is not specified properly.
+SystemError # Raised when the interpreter finds an internal problem, but when this error
+            # is encountered the Python interpreter does not exit.
+SystemExit # Raised when Python interpreter is quit by using the sys.exit() function.
+           # If not handled in the code, causes the interpreter to exit.
+TypeError # Raised when an operation or function is attempted that is invalid for the specified data type.
+ValueError # Raised when the built-in function for a data type has the valid type of arguments,
+           # but the arguments have invalid values specified.
+RuntimeError # Raised when a generated error does not fall into any category.
+NotImplementedError # Raised when an abstract method that needs to be implemented in an
+                    # inherited class is not actually implemented.
+</code>
+<code python>
+# assert Statement
+assert Expression[, Arguments]
+assert (Temperature >= 0), "Colder than absolute zero!"
+# Handling an exception
+try:
+   fh = open("testfile", "w")
+   fh.write("This is my test file for exception handling!!")
+except IOError:
+   print ("Error: can\'t find file or read data")
+except AssertionError, SystemExit:
+   print ("Error: multiple exceptions")
+except ValueError as Argument:
+   print ("The argument does not contain numbers\n", Argument)
+except:
+   print ("Error: all exceptions")
+else:
+   print ("Written content in the file successfully")
+finally:
+   fh.close()
+# Raising an Exception
+raise Exception(level)
+# User-Defined Exceptions
+class Networkerror(RuntimeError):
+   def __init__(self, arg):
+      self.args = arg
+try:
+   raise Networkerror("Bad hostname")
+except Networkerror,e:
+   print e.args
+</code>

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