Python - Error Types

Errors in Python can be classified into

• Compile-time errors
• Runtime errors
• Logical errors

Compile-time errors:

• syntax errors can be classified as compile-time errors
• For example, let us check the output for the below Python block.

x = 0

if x = 0

    print(x)

After compiling above program, output is as below:

 File "F:\python-progrm\Python-Tutorial-1.py", line 10

    if x = 0

         ^

SyntaxError: invalid syntax

We can observe that the line number is indicated with the error line

Run time errors:

• errors reported by Python Virtual Machine (PVM) during the byte code execution
• while syntax errors are compiler-time errors any errors which are syntactically correct and cannot be executed come under run time errors
• Any statement which PVM cannot be executed shall be reported as run time error
• Exception handlers are coded by programmers to handle the run time errors
• for example, let us check the output for the below Python block.

ls = ['0','1']

print(ls[2])

When we run the above block, it reports below error.

File "F:\python-progrm\Python-Tutorial-1.py", line 10, in <module>

    print(ls[2])

IndexError: list index out of range

Logical errors:

• These unlike run time and compiler errors have no relation to the PVM or Python compiler
• These completely are a fault of the programmer because of which intended program output is not achieved
• Example could be while calculating an average of 10 elements, user adding 10 elements but dividing only by 9 gives a wrong output.