python general exception code example

Example 1: raise python

# Raise is used to cause an error
raise(Exception("Put whatever you want here!"))
raise(TypeError)

Example 2: catch error python

import traceback

dict = {'a':3,'b':5,'c':8}
try:
  print(dict[q])
 
except:
  traceback.print_exc()
  
# This will trace you back to the line where everything went wrong. 
# So in this case you will get back line 5

Example 3: how to use except statement in python

>>> def divide(x, y):
...     try:
...         result = x / y
...     except ZeroDivisionError:
...         print("division by zero!")
...     else:
...         print("result is", result)
...     finally:
...         print("executing finally clause")
...
>>> divide(2, 1)
result is 2.0
executing finally clause
>>> divide(2, 0)
division by zero!
executing finally clause
>>> divide("2", "1")
executing finally clause
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<stdin>", line 3, in divide
TypeError: unsupported operand type(s) for /: 'str' and 'str'

Example 4: catch error data with except python

import sys
try:
	S = 1/0 #Create Error
except: # catch *all* exceptions
    e = sys.exc_info()
    print(e) # (Exception Type, Exception Value, TraceBack)

############
#    OR    #
############
try:
	S = 1/0
except ZeroDivisionError as e:
    print(e) # ZeroDivisionError('division by zero')

Example 5: python error handling

try:
	#insert code here
except:
	#insert code that will run if the above code runs into an error.
except ValueError:
	#insert code that will run if the above code runs into a specific error.
	#(For example, a ValueError)

Example 6: python defualt error handler

import sys
def my_except_hook(exctype, value, traceback):
    if exctype == KeyboardInterrupt:
        print "Handler code goes here"
    else:
        sys.__excepthook__(exctype, value, traceback)
sys.excepthook = my_except_hook