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notes_pythons

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notes_pythons [2018/01/05 14:43]
gbdivers 		notes_pythons [2018/02/06 14:32] (Version actuelle)
gbdivers
Ligne 664: Ligne 664:
  
 <code python> <code python>
 +# The import Statement
 +import module1[, module2[,... moduleN]
 +
 # support.py # support.py
 def print_func( par ): def print_func( par ):
Ligne 669: Ligne 672:
    return    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>
 +
 +<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>
 +
  
  
notes_pythons.1515159794.txt.gz · Dernière modification: 2018/01/05 14:43 par gbdivers

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