{"id":107948,"date":"2020-12-09T10:00:00","date_gmt":"2020-12-09T08:00:00","guid":{"rendered":"https:\/\/www.javacodegeeks.com\/?p=107948"},"modified":"2020-12-07T15:37:22","modified_gmt":"2020-12-07T13:37:22","slug":"python-errors-and-built-in-exceptions","status":"publish","type":"post","link":"https:\/\/www.javacodegeeks.com\/python-errors-and-built-in-exceptions.html","title":{"rendered":"Python Errors and Built-in Exceptions"},"content":{"rendered":"

Hello in this tutorial, we will understand errors and built-in exceptions in python programming.<\/p>\n

1. Introduction<\/h2>\n

1.1 Error<\/h3>\n

A typing mistake can lead to a fault in the programming language because of the syntax rules while coding is known as an error or popularly known as the syntax error. A syntax error is the most common situation where you break any syntax rule. The snippet below is a good example of a syntax error where we missed to specify the colon at the end of the if<\/code> condition.<\/p>\n

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# Syntax error<\/code><\/div>\n
# Reason - Invalid syntax as you have not added colon (:) at the end of if condition.<\/code><\/div>\n
if<\/code> 7<\/code> > <\/code>5<\/code>:<\/code><\/div>\n
    <\/code>print<\/code>(<\/code>'True'<\/code>)<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

1.2 Exceptions<\/h3>\n

An exception is considered as an unusual condition in a program that breaks the program flow due to an interruption. When an exception occurs, the program stops, and the further code is not executed and thus they are also known as the run-time errors. An exception in python is an object that represents the error and Exception<\/code> is python is known as the base class for all exceptions. The table below lists the built-in exception that usually occurs in python programming.<\/p>\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
Exception<\/strong><\/th>\n<\/th>\n<\/tr>\n<\/thead>\n
ArithmeticError<\/code><\/td>\nRaised when an error occurs in numeric calculations<\/td>\n<\/tr>\n
AssertionError<\/code><\/td>\nRaised when an assert statement fails<\/td>\n<\/tr>\n
AttributeError<\/code><\/td>\nRaised when attribute reference or assignment fails<\/td>\n<\/tr>\n
EOFError<\/code><\/td>\nRaised when the input()<\/code> method hits an end of file condition<\/td>\n<\/tr>\n
FloatingPointError<\/code><\/td>\nRaised when a floating-point calculation fails<\/td>\n<\/tr>\n
ImportError<\/code><\/td>\nRaised when an imported module does not exist<\/td>\n<\/tr>\n
IndentationError<\/code><\/td>\nRaised when indentation is not correct<\/td>\n<\/tr>\n
IndexError<\/code><\/td>\nRaised when an index of a sequence does not exist<\/td>\n<\/tr>\n
KeyError<\/code><\/td>\nRaised when a key does not exist in a dictionary<\/td>\n<\/tr>\n
MemoryError<\/code><\/td>\nRaised when a program runs out of memory<\/td>\n<\/tr>\n
NameError<\/code><\/td>\nRaised when a variable does not exist<\/td>\n<\/tr>\n
NotImplementedError<\/code><\/td>\nRaised when an abstract method requires an inherited class to override the method<\/td>\n<\/tr>\n
OverflowError<\/code><\/td>\nRaised when the result of a numeric calculation is too large<\/td>\n<\/tr>\n
ReferenceError<\/code><\/td>\nRaised when a weak reference object does not exist<\/td>\n<\/tr>\n
RuntimeError<\/code><\/td>\nRaised when an error occurs that does not belong to any specific expectations<\/td>\n<\/tr>\n
StopIteration<\/code><\/td>\nRaised when the next()<\/code> method of an iterator has no further values<\/td>\n<\/tr>\n
SyntaxError<\/code><\/td>\nRaised when a syntax error occurs<\/td>\n<\/tr>\n
TabError<\/code><\/td>\nRaised when indentation consists of tabs or spaces<\/td>\n<\/tr>\n
SystemError<\/code><\/td>\nRaised when a system error occurs<\/td>\n<\/tr>\n
SystemExit<\/code><\/td>\nRaised when the sys.exit()<\/code> function is called<\/td>\n<\/tr>\n
TypeError<\/code><\/td>\nRaised when two different types are combined<\/td>\n<\/tr>\n
ValueError<\/code><\/td>\nRaised when there is a wrong value in a specified data type<\/td>\n<\/tr>\n
ZeroDivisionError<\/code><\/td>\nRaised when the second operator in a division is zero<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

1.3 Setting up Python<\/h3>\n

If someone needs to go through the Python installation on Windows, please watch this<\/a> link. You can download the Python from this<\/a> link.

<\/div> <\/div><\/p>\n

2. Python Errors and Built-in Exceptions<\/h2>\n

I am using JetBrains PyCharm<\/a> as my preferred IDE. You are free to choose the IDE of your choice.<\/p>\n

2.1 SyntaxError<\/h3>\n

Let us understand this with the help of a code snippet.<\/p>\n

SyntaxError<\/em><\/span><\/p>\n

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# Syntax error<\/code><\/div>\n
# Reason - From Python3 onwards print statement has changed and expects the parenthesis.<\/code><\/div>\n
print<\/code>(<\/code>'Hello world from Python!'<\/code>)<\/code><\/div>\n
# Syntax error<\/code><\/div>\n
# Reason - Invalid syntax as you have not added colon (:) at the end of if condition.<\/code><\/div>\n
if<\/code> 7<\/code> > <\/code>5<\/code>:<\/code><\/div>\n
    <\/code>print<\/code>(<\/code>'True'<\/code>)<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

If everything goes well the syntax error warnings will be shown in the IDE console.<\/p>\n

Console Output<\/em><\/span><\/p>\n

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== syntax error ==<\/code><\/div>\n
print 'Hello world from Python!'<\/code><\/div>\n
          <\/code>^<\/code><\/div>\n
SyntaxError: Missing parentheses in call to 'print'. Did you mean print('Hello world from Python!')?<\/code><\/div>\n
<\/div>\n
if 7 > 5<\/code><\/div>\n
           <\/code>^<\/code><\/div>\n
SyntaxError: invalid syntax<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

2.2 ZeroDivisionError<\/h3>\n

Let us understand this with the help of a code snippet.<\/p>\n

ZeroDivisionError<\/em><\/span><\/p>\n

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# Python exception example<\/code><\/div>\n
a <\/code>=<\/code> 10<\/code><\/div>\n
b <\/code>=<\/code> 0<\/code><\/div>\n
c <\/code>=<\/code> a <\/code>\/<\/code> b<\/code><\/div>\n
print<\/code>(<\/code>'Result of division = {}'<\/code>.<\/code>format<\/code>(<\/code>str<\/code>(c)))<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

If everything goes well the following error output will be shown in the IDE console.<\/p>\n

Console Output<\/em><\/span><\/p>\n

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Traceback (most recent call last):<\/code><\/div>\n
  <\/code>File \"jcg-assignment-python-error-and-exceptions.py\", line 15, in <\/code><\/div>\n
    <\/code>c = a \/ b<\/code><\/div>\n
ZeroDivisionError: division by zero<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

That is all for this tutorial and I hope the article served you with whatever you were looking for. Happy Learning and do not forget to share!<\/p>\n

3. Summary<\/h2>\n

In this tutorial, we learned:<\/p>\n