Python is easy to learn and code, but small mistakes can cause bugs and ruin your software. Catching those mistakes and fixing them on time is very important. Learning about those mistakes is very important especially for beginner developers.
In this article we are going to learn about the problems that cause bugs in your python code and how you can fix those.
Expressions as function arguments
Python programmer for hire often use expression as function argument which is optional then have to provide default values. This feature is confusing sometimes and developers set the default value to a mutable object.
Optional arguments are not set to default value provided, each time function is called without the argument default value.
Check out this code
Here, every time the method was called it kept appending the value to the list and printed it. The program ran for the length of the append string.
What it should have done was to print the append string value once each time in a new line.
What actually happened is that the default value is executed only once. That is when the function is once defined. Further on it continued to use the value which was defined initially.
Here is the fix for python programmer for hire. All done is that the initial value of bar is set to none.
Class variables
Class variables are treated as dictionaries but beginner python developers forget that. They work on the MRO principle. In the following code X is the property of A class but when you print C it will look up in the base class. So, C does not have its own X property but is related to A. When we change the value of A,B the value of C is also changed because it is related.
Exception block parameters
Stating the parameters of the exception block incorrectly can not only cause the program to crash but it can cause bugs in the program. Catching the bugs is very important to save your software from crashing. Exception block, try and catch, is your protection against the inconvenience and unexpected user inputs. Python coders do use the exception handling but using it right is important.
Coding an exception block this way will cause the program to break down giving invalid syntax, stating that the except statement does not accept multiple values. The index error is not caught by the program but it ends up in the parameter.
What you can do is list the values as parameters in tuple and you will get the right output.
Python scope rules
Understanding scope for python developers is very important. This is confusing for many people because it seems that scope rules are straight forward but it actually is not. Here is an example to help you understand better.
Assigning a variable a value in global scope. Which is what most python programmer for hire are mistaking. Defining a variable before the function counts it as global so any similarly named variable defined after is shadowed.
The solution is simple: you can simply use lists instead of using a variable and the code works just fine. However, to add a value to the list you have to use the append method and you cannot use the “+=” which is for a variable. Similarly, to read and delete values from the list you have to use the list methods specified for the operation required.
Naming convention
Naming convention might not seem as important a topic but it causes problems, even for the experienced python developers.
Avoiding clashes i.e. naming variables and functions etc. similar to the python libraries is hard. So, you have to deliberately keep trying not to have a similar naming.
The bad thing is that python comes with a huge list of libraries so avoiding naming anything that matches with the libraries is difficult. But there is a solution. For instance if you are defining your own add function then instead of naming it add or addition you should do “add_custom”.
