initialcommit

Author: HashimThePassionate

20-Modules.py

@@ -6,14 +6,14 @@
 need to keep repeating ourselves.
 DRY!....Don't repeat yourself
 '''
-import example
-example.add(4,5.5)
+import ModuleExample
+ModuleExample.add(4,5.5)
 
 #We can import a module by renaming it as follows:
 # import module by renaming it
 
-import example as m
-print("The addition is ",example.add(4,5.5))
+import ModuleExample as m
+print("The addition is ",m.add(4,5.5))
 
 #Python import statement
 # import statement example

21-ExceptionHandling.py

@@ -0,0 +1,245 @@
+#What is exception handling
+'''
+Exception handling is the process of responding to unwanted 
+or unexpected events when a computer program runs. Exception 
+handling deals with these events to avoid the program or 
+system crashing, and without this process, 
+exceptions would disrupt the normal operation of a program.
+
+a=1
+while a:
+    a=a+1
+    print(a)
+    
+''' 
+#Python Exceptions
+'''
+A Python program terminates as soon as it encounters an error. 
+In Python, an error can be a "syntax error" or an "exception".
+'''
+'''
+Syntax errors: Also known as parsing errors, are perhaps the 
+most common kind of complaint you get while you are still 
+learning Python.
+
+Exceptions: This type of error occurs whenever syntactically 
+correct Python code results in an error. The last line of 
+the message indicated what type of exception error you ran into.
+
+Here are all of Pythons built-in exception
+1.ArithmeticError Raised when an error occurs in numeric calculations
+2.AssertionError Raised when an assert statement fails
+3.AttributeError Raised when attribute reference or assignment fails
+4.Exception Base class for all exceptions
+5.EOFError Raised when the input() method hits an "end of file" 
+condition (EOF)
+6.FloatingPointError Raised when a floating point calculation fails
+7.GeneratorExit Raised when a generator is closed (with the close() 
+method)
+8.ImportError Raised when an imported module does not exist
+9.IndentationError Raised when indentation is not correct
+10.IndexError Raised when an index of a sequence does not exist
+11.KeyError Raised when a key does not exist in a dictionary
+12.KeyboardInterrupt Raised when the user presses Ctrl+c, Ctrl+z or 
+Delete
+13.LookupError Raised when errors raised cant be found
+14.MemoryError Raised when a program runs out of memory
+15.NameError Raised when a variable does not exist
+16.NotImplementedError Raised when an abstract method requires 
+an inherited class to override the method
+17.OSError Raised when a system related operation causes an error
+18.OverflowError Raised when the result of a numeric calculation is 
+too large
+19.ReferenceError Raised when a weak reference object does 
+not exist
+20.RuntimeError Raised when an error occurs that do not belong 
+to any specific expections
+21.StopIteration Raised when the next() method of an iterator 
+has no further values
+22.SyntaxError Raised when a syntax error occurs
+23.TabError Raised when indentation consists of tabs or spaces
+24.SystemError Raised when a system error occurs
+25.SystemExit Raised when the sys.exit() function is called
+26.TypeError Raised when two different types are combined
+27.UnboundLocalError Raised when a local variable is referenced 
+before assignment
+28.UnicodeError Raised when a unicode problem occurs
+29.UnicodeEncodeError Raised when a unicode encoding problem occurs
+30.UnicodeDecodeError Raised when a unicode decoding problem occurs
+31.UnicodeTranslateError Raised when a unicode translation problem 
+occurs
+32.ValueError Raised when there is a wrong value in a specified 
+data type
+33.ZeroDivisionError Raised when the second operator in a 
+division is zero
+'''
+
+#Syntax error
+'''
+a=2
+a++ #Error 
+a=a+1
+a
+'''
+#ZeroDivisionError 
+a=2
+c=0
+d=a/c
+'''
+Traceback (most recent call last):
+  File "<stdin>", line 1, in <module>
+"ZeroDivisionError: division by zero"
+'''
+#The Raising an Exception
+'''
+We can use raise to throw an exception if a condition occurs. 
+The statement can be complemented with a custom exception.
+
+If a condition does not meet our criteria but is correct according to 
+the Python interpreter, we can intentionally raise an exception using 
+the raise keyword
+
+If you want to throw an error when a certain condition occurs 
+using raise, you could go about it like this:
+'''
+#Example1
+x = 10
+if x > 5:
+    raise Exception('x should not exceed 5. The value of x was: {}'.format(x))
+
+'''
+Traceback (most recent call last):
+  File "<input>", line 4, in <module>
+Exception: x should not exceed 5. The value of x was: 10
+'''
+
+#Example2
+num = [3, 4, 5, 7]  
+if len(num) > 3:  
+    raise Exception( f"Length of the given list must be less than or equal to 3 but is {len(num)}" ) 
+'''
+Traceback (most recent call last):
+  File "<stdin>", line 2, in <module>
+Exception: Length of the given list must be less than or equal to 3 but is 4
+'''
+
+#The AssertionError Exception
+'''
+The simplest way to understand an assertion to check the condition.
+If it finds that the condition is true, it moves to the next line of 
+code, and If not, then stops all its operations and throws an error.
+It points out the error in the code.
+assert Expressions[, Argument]
+
+If this condition turns out to be True, then that is excellent! 
+The program can continue. If the condition turns out to be False, 
+you can have the program throw an AssertionError exception.
+'''
+#Example1
+def square_root( Number ):  
+    assert ( Number < 0), "Give a positive integer"  
+    return Number**(1/2)  
+  
+#Calling function and passing the values  
+print( square_root(-36))  
+print( square_root(36)) 
+
+'''
+Output
+(3.6739403974420594e-16+6j)
+
+Traceback (most recent call last):
+  File "<stdin>", line 1, in <module>
+  File "<stdin>", line 2, in square_root
+AssertionError: Give a positive integer)
+'''
+#Example2
+def avg(scores):    
+    assert len(scores) != 0,"The List is empty."    
+    return sum(scores)/len(scores)    
+scores2 = [67,59,86,75,92]    
+print("The Average of scores2:",avg(scores2))    
+scores1 = []    
+print("The Average of scores1:",avg(scores1))   
+
+'''
+The Average of scores2: 75.8
+
+Traceback (most recent call last):
+  File "<stdin>", line 1, in <module>
+  File "<stdin>", line 2, in avg
+AssertionError: The List is empty.
+'''
+
+#The try and except Block
+'''
+In Python, we catch exceptions and handle them using try and except 
+code blocks. The try clause contains the code that can raise an 
+exception, while the except clause contains the code lines that handle 
+the exception. Let's see if we can access the index from the array, 
+which is more than the array's length, and handle the resulting 
+exception.
+'''
+#Example
+a = ["Python", "Exceptions", "try and except"]  
+try:  
+    #looping through the elements of the array a, choosing a range that goes beyond the length of the array  
+     for i in range( 4 ):  
+        print( "The index and element from the array is", i, a[i] )  
+#if an error occurs in the try block, then except block will be executed by the Python interpreter       
+except:  
+    print ("Index out of range")  
+'''
+
+Output
+The index and element from the array is 0 Python
+The index and element from the array is 1 Exceptions
+The index and element from the array is 2 try and except
+Index out of range
+
+'''
+#Try with Else Clause
+'''
+If there is no exception, this code block will be executed by 
+the Python interpreter 
+'''
+def reciprocal( num1 ):  
+    try:  
+        reci = 1 / num1  
+    except ZeroDivisionError:  
+        print( "We cannot divide by zero" )  
+    else:  
+        print ( reci )  
+# Calling the function and passing values  
+reciprocal( 4 )  
+reciprocal( 0 )
+
+'''
+0.25
+"We cannot divide by zero" 
+'''
+
+#Finally Keyword in Python
+'''
+The finally keyword is available in Python, and it is always used 
+after the try-except block. The finally code block is always executed 
+after the try block has terminated normally or after the try block 
+has terminated for some other reason.
+'''
+# Python code to show the use of finally clause  
+
+try:  
+    div = 4 / 0    
+    print( div )  
+# this block will handle the exception raised  
+except ZeroDivisionError:  
+    print( "Attepting to divide by zero" )  
+# this will always be executed no matter exception is raised or not  
+finally:  
+    print( 'This is code of finally clause' )  
+
+'''
+Output
+Atepting to divide by zero
+This is code of finally clause
+'''