Python: Key Words and Phrases

Python Overview

Keyword Description
and A logical operator
as To create an alias
assert For debugging
break To break out of a loop
class To define a class
continue To continue to the next iteration of a loop
def To define a function
del To delete an object
elif Used in conditional statements, same as else if
else Used in conditional statements
except Used with exceptions, what to do when an exception occurs
False Boolean value, result of comparison operations
finally Used with exceptions, a block of code that will be executed no matter if there is an exception or not
for To create a for loop
from To import specific parts of a module
global To declare a global variable
if To make a conditional statement
import To import a module
in To check if a value is present in a list, tuple, etc.
is To test if two variables are equal
lambda To create an anonymous function
None Represents a null value
nonlocal To declare a non-local variable
not A logical operator
or A logical operator
pass A null statement, a statement that will do nothing
raise To raise an exception
return To exit a function and return a value
True Boolean value, result of comparison operations
try To make a try…except statement
while To create a while loop
with Used to simplify exception handling
yield To return a list of values from a generator

 

Built-in Exceptions

The table below shows built-in exceptions that are usually raised in Python:

Exception Description
ArithmeticError Raised when an error occurs in numeric calculations
AssertionError Raised when an assert statement fails
AttributeError Raised when attribute reference or assignment fails
Exception Base class for all exceptions
EOFError Raised when the input() method hits an “end of file” condition (EOF)
FloatingPointError Raised when a floating point calculation fails
GeneratorExit Raised when a generator is closed (with the close() method)
ImportError Raised when an imported module does not exist
IndentationError Raised when indentation is not correct
IndexError Raised when an index of a sequence does not exist
KeyError Raised when a key does not exist in a dictionary
KeyboardInterrupt Raised when the user presses Ctrl+c, Ctrl+z or Delete
LookupError Raised when errors raised cant be found
MemoryError Raised when a program runs out of memory
NameError Raised when a variable does not exist
NotImplementedError Raised when an abstract method requires an inherited class to override the method
OSError Raised when a system related operation causes an error
OverflowError Raised when the result of a numeric calculation is too large
ReferenceError Raised when a weak reference object does not exist
RuntimeError Raised when an error occurs that do not belong to any specific exceptions
StopIteration Raised when the next() method of an iterator has no further values
SyntaxError Raised when a syntax error occurs
TabError Raised when indentation consists of tabs or spaces
SystemError Raised when a system error occurs
SystemExit Raised when the sys.exit() function is called
TypeError Raised when two different types are combined
UnboundLocalError Raised when a local variable is referenced before assignment
UnicodeError Raised when a unicode problem occurs
UnicodeEncodeError Raised when a unicode encoding problem occurs
UnicodeDecodeError Raised when a unicode decoding problem occurs
UnicodeTranslateError Raised when a unicode translation problem occurs
ValueError Raised when there is a wrong value in a specified data type
ZeroDivisionError Raised when the second operator in a division is zero

 

Built-in Exceptions

https://www.w3schools.com/python/python_ref_exceptions.asp

https://www.w3schools.com/python/python_ref_glossary.asp

The table below shows built-in exceptions that are usually raised in Python:

Exception Description
ArithmeticError Raised when an error occurs in numeric calculations
AssertionError Raised when an assert statement fails
AttributeError Raised when attribute reference or assignment fails
Exception Base class for all exceptions
EOFError Raised when the input() method hits an “end of file” condition (EOF)
FloatingPointError Raised when a floating point calculation fails
GeneratorExit Raised when a generator is closed (with the close() method)
ImportError Raised when an imported module does not exist
IndentationError Raised when indentation is not correct
IndexError Raised when an index of a sequence does not exist
KeyError Raised when a key does not exist in a dictionary
KeyboardInterrupt Raised when the user presses Ctrl+c, Ctrl+z or Delete
LookupError Raised when errors raised cant be found
MemoryError Raised when a program runs out of memory
NameError Raised when a variable does not exist
NotImplementedError Raised when an abstract method requires an inherited class to override the method
OSError Raised when a system related operation causes an error
OverflowError Raised when the result of a numeric calculation is too large
ReferenceError Raised when a weak reference object does not exist
RuntimeError Raised when an error occurs that do not belong to any specific exceptions
StopIteration Raised when the next() method of an iterator has no further values
SyntaxError Raised when a syntax error occurs
TabError Raised when indentation consists of tabs or spaces
SystemError Raised when a system error occurs
SystemExit Raised when the sys.exit() function is called
TypeError Raised when two different types are combined
UnboundLocalError Raised when a local variable is referenced before assignment
UnicodeError Raised when a unicode problem occurs
UnicodeEncodeError Raised when a unicode encoding problem occurs
UnicodeDecodeError Raised when a unicode decoding problem occurs
UnicodeTranslateError Raised when a unicode translation problem occurs
ValueError Raised when there is a wrong value in a specified data type
ZeroDivisionError Raised when the second operator in a division is zero