Exception handling

Exception handling¶

Exceptions are classes. You can define your own by inheriting from Exception class.

try:
    statements

except Exception_type1 as e1:
    handling statements

except Exception_type2 as e2:
    specific handling statements

except Exception as generic_ex:
    generic handling statements

else:
    some more statements  # executes if no exceptions were fired

finally:
    default statements which will always be executed  # put logic such as conn close / mem release statements here

In [13]:

try:
    img2 = ImageryObject("user\img\file2.img")
    img2.display()
except:
    print("something bad happened")

try: img2 = ImageryObject("user\img\file2.img") img2.display() except: print("something bad happened")

image is displayed

In [14]:

try:
    img2 = ImageryObject("user\img\file2.img")
    img2.display()
except:
    print("something bad happened")
else:
    print("else block")
finally:
    print("finally block")

try: img2 = ImageryObject("user\img\file2.img") img2.display() except: print("something bad happened") else: print("else block") finally: print("finally block")

image is displayed
else block
finally block

In [15]:

try:
    img2 = ImageryObject()
    img2.display()
except:
    print("something bad happened")
else:
    print("else block")
finally:
    print("finally block")

try: img2 = ImageryObject() img2.display() except: print("something bad happened") else: print("else block") finally: print("finally block")

something bad happened
finally block

In [21]:

try:
    img2 = ImageryObject()
    img2.display()

except Exception as ex:
    print("something bad happened")
    print("exactly what whent bad? : " + str(ex))

try: img2 = ImageryObject() img2.display() except Exception as ex: print("something bad happened") print("exactly what whent bad? : " + str(ex))

something bad happened
exactly what whent bad? : __init__() missing 1 required positional argument: 'file_path'

In [22]:

try:
    img2 = ImageryObject('path')
    img2.dddisplay()

except TypeError as terr:
    print("looks like you forgot a parameter")
except Exception as ex:
    print("nope, it went worng here: " + str(ex))

try: img2 = ImageryObject('path') img2.dddisplay() except TypeError as terr: print("looks like you forgot a parameter") except Exception as ex: print("nope, it went worng here: " + str(ex))

nope, it went worng here: 'ImageryObject' object has no attribute 'dddisplay'

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