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Handeling Errors

Learning from Errors

    1. What is wrong here?
# This is title

This is paragraph

---------------------------------------------------------------------------

NameError                                 Traceback (most recent call last)

<ipython-input-1-9784fba40ee2> in <module>
      1 # This is title
      2 
----> 3 This is paragraph


NameError: name 'This' is not defined

Note: Learn more about Jupyter notebook functionalities

    1. What is wrong here?
print "Hello world"

  File "<ipython-input-3-9fb80848b1b7>", line 1
    print "Hello world"
                      ^
SyntaxError: Missing parentheses in call to 'print'. Did you mean print("Hello world")?
    1. What is wrong here?
for i in range(4):
print(i)

  File "<ipython-input-5-8ee9e742a8b8>", line 2
    print(i)
        ^
IndentationError: expected an indented block
    1. What is wrong here?
L = [3,5,7]
L[3]

---------------------------------------------------------------------------

IndexError                                Traceback (most recent call last)

<ipython-input-13-e5031a802bc6> in <module>
      1 L = [3,5,7]
----> 2 L[3]


IndexError: list index out of range
    1. What is wrong here?
A = npp.array([2,5,7])

---------------------------------------------------------------------------

NameError                                 Traceback (most recent call last)

<ipython-input-8-c9813575a7f9> in <module>
----> 1 A = npp.array([2,5,7])


NameError: name 'npp' is not defined

def myfunction():
    x = random.randint()
    return x+10

myfunction()

---------------------------------------------------------------------------

NameError                                 Traceback (most recent call last)

<ipython-input-16-7b999452a26c> in <module>
----> 1 myfunction()


<ipython-input-15-6920121cfd0d> in myfunction()
      1 def myfunction():
----> 2     x = random.randint()
      3     return x+10


NameError: name 'random' is not defined

def myfunction(x):
    return x+y

myfunction(5)

---------------------------------------------------------------------------

NameError                                 Traceback (most recent call last)

<ipython-input-18-8afb436c6a81> in <module>
----> 1 myfunction(5)


<ipython-input-17-29ec7037f18c> in myfunction(x)
      1 def myfunction(x):
----> 2     return x+y


NameError: name 'y' is not defined

def myfunction(x):
    y=6
    return x+y

myfunction(5)

11

y

---------------------------------------------------------------------------

NameError                                 Traceback (most recent call last)

<ipython-input-22-9063a9f0e032> in <module>
----> 1 y


NameError: name 'y' is not defined
  1. What is wrong here?
for i in range(5):
    print(5/i)

---------------------------------------------------------------------------

ZeroDivisionError                         Traceback (most recent call last)

<ipython-input-29-7f38f68db52f> in <module>
      1 for i in range(5):
----> 2     print(5/i)


ZeroDivisionError: division by zero



open("imaginary.txt")

---------------------------------------------------------------------------

FileNotFoundError                         Traceback (most recent call last)

<ipython-input-30-2bedf9c67314> in <module>
----> 1 open("imaginary.txt")


FileNotFoundError: [Errno 2] No such file or directory: 'imaginary.txt'

L = [1,2,3,4]
type(L)

list

for k,v in L.items():
    print(k,v)

---------------------------------------------------------------------------

AttributeError                            Traceback (most recent call last)

<ipython-input-22-1284dd3b8bca> in <module>
----> 1 for k,v in L.items():
      2     print(k,v)


AttributeError: 'list' object has no attribute 'items'

Types of Error:

Learn more about Python errors

Exception Cause of Error
AssertionError Raised when an assert statement fails.
AttributeError Raised when attribute assignment or reference fails.
EOFError Raised when the input() function hits end-of-file condition.
FloatingPointError Raised when a floating point operation fails.
GeneratorExit Raise when a generator's close() method is called.
ImportError Raised when the imported module is not found.
IndexError Raised when the index of a sequence is out of range.
KeyError Raised when a key is not found in a dictionary.
KeyboardInterrupt Raised when the user hits the interrupt key (Ctrl+C or Delete).
MemoryError Raised when an operation runs out of memory.
NameError Raised when a variable is not found in local or global scope.
NotImplementedError Raised by abstract methods.
OSError Raised when system operation causes system related error.
OverflowError Raised when the result of an arithmetic operation is too large to be represented.
ReferenceError Raised when a weak reference proxy is used to access a garbage collected referent.
RuntimeError Raised when an error does not fall under any other category.
StopIteration Raised by next() function to indicate that there is no further item to be returned by iterator.
SyntaxError Raised by parser when syntax error is encountered.
IndentationError Raised when there is incorrect indentation.
TabError Raised when indentation consists of inconsistent tabs and spaces.
SystemError Raised when interpreter detects internal error.
SystemExit Raised by sys.exit() function.
TypeError Raised when a function or operation is applied to an object of incorrect type.
UnboundLocalError Raised when a reference is made to a local variable in a function or method, but no value has been bound to that variable.
UnicodeError Raised when a Unicode-related encoding or decoding error occurs.
UnicodeEncodeError Raised when a Unicode-related error occurs during encoding.
UnicodeDecodeError Raised when a Unicode-related error occurs during decoding.
UnicodeTranslateError Raised when a Unicode-related error occurs during translating.
ValueError Raised when a function gets an argument of correct type but improper value.
ZeroDivisionError Raised when the second operand of division or modulo operation is zero.

Exception Handeling

Learn more in builtin exceptions

D = {"1344":234.98,"2564":345.97,"3345":367.95,"#":358.63,"*":283.54}

for k,v in D.items():
        k = int(k)

---------------------------------------------------------------------------

ValueError                                Traceback (most recent call last)

<ipython-input-2-6fae1746f8e5> in <module>
      1 for k,v in D.items():
----> 2         k = int(k)


ValueError: invalid literal for int() with base 10: '#'

int_dict = {}
non_int_dict = {}
for k,v in D.items():
    try:
        int_dict.update({int(k):v})
        print("this is integer", k)
    except:
        non_int_dict.update({k:v})
        print('this is not integer',k)

this is integer 1344
this is integer 2564
this is integer 3345
this is not integer #
this is not integer *

int_dict

{1344: 234.98, 2564: 345.97, 3345: 367.95}

non_int_dict

{'#': 358.63, '*': 283.54}