What This Tutorial Is Not
This tutorial does not aim to cover every available workplace culture – different employers will ask you different questions in different ways they will follow different conventions they will value different things. They will test you in different ways. Some employers will sit you down in from of a computer and ask you to solve simple problems some will stand you up in front of a white board and do similar some will give you a take home test to solve some will just have a conversation with you.
The best test for a programmer is actually programming. This is a difficult thing to test with a simple tutorial. So for bonus points make sure that you can actually use the functionality demonstrated in the questions. If you actually understand how to get to the answers well enough that you can actually make use of the demonstrated concepts then you are winning.
Similarly, the best test for a software engineer is actually engineering. This tutorial is about Python as a language. Being able to design efficient, effective, maintainable class hierarchies for solving niche problems is great and wonderful and a skill set worth pursuing but well beyond the scope of this text.
Another thing this tutorial is not is PEP8 compliant. This is intentional as, as mentioned before, different employers will follow different conventions. You will need to adapt to fit the culture of the workplace. Because practicality beats purity.
What Are Data Frames
A pandas dataframe is a data structure in pandas that is mutable. Pandas have support for heterogeneous data which is arranged across two axes. .
Reading files into pandas:-
Import pandas as pddf=p.read_csv
Here df is a pandas data frame. read_csv is used to read a comma-delimited file as a dataframe in pandas.
Does Python Support Operator Overloading How
Certain non-alphanumeric characters are defined to perform a specified operation. Such characters are called operators. For example the characters +, -, * and / are defined to perform arithmetic operations on two numeric operands. Similarly < , > == and != perform comparison of two numeric operands by default.
Some of built-in classes of Python allow certain operators to be used with non-numeric objects too. For instance the + operator acts as concatenation operator with two strings. We say that + operator is overloaded. In general overloading refers to attaching additional operation to the operator.
> > > #default addition operation of +> > > 2+57> > > #+operator overloaded as concatenation operator> > > 'Hello'+'Python''HelloPython'> > > +> > > #default multiplication operation of *> > > 2*510> > > #overloaded * operator as repetition operation with sequences> > > *3> > > 'Hello'*3'HelloHelloHello'
For user defined classes, operator overloading is achieved by overriding relevant magic methods from the object class. For example, if a class contains overridden definition of __add__ method, it is implemented when + operator is used with objects of that class. Following table shows magic methods and the arithmetic operator they implement:
| Operator |
|---|
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What Is A User Defined Exception How Is It Raised In Python Script
Errors detected during execution are called exceptions. In Python, all exceptions must be instances of a class that derives from BaseException. Python library defines many subclasses of BaseException. They are called built-in exceptions. Examples are TypeError, ValueError etc.
When user code in try: block raises an exception, program control is thrown towards except block of corresponding predefined exception type. However, if the exception is different from built-in ones, user can define a customized exception class. It is called user defined exception.
Following example defines MyException as a user defined exception.
class MyException: def __init__: self.num=num def __str__: return "MyException: invalid number"+str
Built-in exceptions are raised implicitly by the Python interpreter. However, exceptions of user defined type must be raised explicitly by using raise keyword.
The try: block accepts a number from user and raises MyException if the number is beyond the range 0-100. The except block then processes the exception object as defined.
try: x=int) if x not in range: raise MyException print except MyException as m: print
Output:
Obviously, print is most commonly used Python statements and is used to display the value of one or more objects. However, it accepts other arguments other than objects to be displayed.
> > > x=10> > > y=20> > > z=30> > > print 10 20 30> > > #using comma as separator> > > print 10,20,30
newclass=type
> > > user=type, )
Output:
extend:
Devops Interview Questions: Important Python Questions
In few of the previous articles we started talking about questions that can come in DevOps and SRE interviews. In this article, we are continuing the trend by bringing you the python questions that can come in the interviews. You can look at the last article below.
DevOps Interview Question: How will you set up a CI/CD pipeline?
When we talk about python involvement in DevOps, it is very much important as in the basic day to day automation can be easily automated. It is also used widely in DevOps tools and learning this will take you to the next level. Now lets see the questions that can come in interviews.
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Devops Interview Questions And Answers For 2022
The employment market is highly competitive, and interview questions for DevOps engineers can cover a wide range of topics. If you’ve begun preparing for development and operations responsibilities in the IT business, you’re already aware that it’s a challenging profession to break into. Here are some of the most frequently asked DevOps interview questions and answers to help you prepare for DevOps engineer jobs in the industry.
What Is The Use Of Self In Python
Self is used to represent the instance of the class. With this keyword, you can access the attributes and methods of the class in python. It binds the attributes with the given arguments. self is used in different places and often thought to be a keyword. But unlike in C++, self is not a keyword in Python.
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What Is A Merge Conflict In Git And How Can It Be Resolved
A Git merge conflict happens when you have merge branches with competing for commits, and Git needs your help to decide which changes to incorporate in the final merge.
Manually edit the conflicted file to select the changes that you want to keep in the final merge.
Resolve using GitHub conflict editor
This is done when a merge conflict is caused after competing for line changes. For example, this may occur when people make different changes to the same line of the same file on different branches in your Git repository.
- Resolving a merge conflict using conflict editor:
- Under your repository name, click “Pull requests.”
- In the “Pull requests” drop-down, click the pull request with a merge conflict that you’d like to resolve
- Near the bottom of your pull request, click “Resolve conflicts.”
- Delete the conflict markers < < < < < < < , =======, > > > > > > > and make changes you want in the final merge.
- If you have more than one merge conflict in your file, scroll down to the next set of conflict markers and repeat steps four and five to resolve your merge conflict.
- Once you have resolved all the conflicts in the file, click Mark as resolved.
- If you have more than one file with a conflict, select the next file you want to edit on the left side of the page under “conflicting files” and repeat steps four to seven until you’ve resolved all of your pull request’s merge conflicts.
- Delete the conflict markers “< < < < < < < “, “=======”, “> > > > > > > ” and make the changes you want in the final merge.
What Are The Benefits Of Automation Testing
Some of the advantages of Automation Testing are –
- Helps to save money and time.
- Unattended execution can be easily done.
- Huge test matrices can be easily tested.
- Parallel execution is enabled.
- Reduced human-generated errors, which results in improved accuracy.
- Repeated test tasks execution is supported.
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Python Shell Scripting Interview Questions For Practice
Whenever Python Exits Why Isnt All The Memory De
- Whenever Python exits, especially those Python modules which are having circular references to other objects or the objects that are referenced from the global namespaces are not always de-allocated or freed.
- It is not possible to de-allocate those portions of memory that are reserved by the C library.
- On exit, because of having its own efficient clean up mechanism, Python would try to de-allocate every object.
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What Are Various String Formatting Features Available In Python
Format specification symbols are popularly used in C/C++ for formatting strings. These symbols can be used in Python also. Just as in C, a string is constructed by substituting these symbols with Python objects.
In the example below, we use the symbols %s and %d in the string and substitute them by values of objects in tuple outside the string, prefixed by % symbol
> > > name='Ravi'> > > age=21> > > string="Hello. My name is %s. I am %d years old" %> > > string'Hello. My name is Ravi. I am 21 years old'
In numeric formatting symbols, the width of number can be specified before and/or after a decimal point.
> > > price=50> > > weight=21.55> > > string="price=%3d weight=%3.3f" %> > > string'price= 50 weight=21.550'
Since Python 3.x a new format method has been added in built-in string class which is more efficient and elegant, and is prescribed to be the recommended way of formatting with variable substitution.
Instead of % formatting operator, symbols are used as place holders.
> > > name='Ravi'> > > age=21> > > string="Hello. My name is . I am years old".format> > > string'Hello. My name is Ravi. I am 21 years old'
Format specification symbols are used with : instead of %. So to insert a string in place holder use and for integer use . Width of numeric and string variables is specified as before.
> > > price=50> > > weight=21.55> > > string="price= quantity=".format> > > string'price= 50 quantity=21.550'
As would be expected, expression without railing comma declares an int object.
Coding Interview Question For Screening Devops Candidates
Many companies practice coding interview in their developer hiring process. The candidate is asked to solve a programming problem in a fixed time-frame to demonstrate their proficiency in the skill the company is looking to hire for. This practice to a certain degree differentiates candidates who can’t do real work but somehow got past the first non-technical interview from those who can.
The question in a coding interview is usually a tricky problem involving the use of data structure or algorithm, because that will test the candidate’s fundamental understanding of computer science. What if you are hiring a DevOps person? Clearly data structure and algorithm aren’t so critical in DevOps tasks. What kind of question is better for testing DevOps candidate? A lot of recruiters have no clue.
This is a question I have used before and had considerable success with:
Automate the process of granting / revoking SSH access to a group of servers instances to a new developer.
This question is so basic that a candidate who fails to do this cannot call himself a DevOps engineer. SSH public key authentication is fundamental in Linux system administration. Automating process is a fundamental responsibility of a DevOps engineer.
You can check how he plans ahead and how he properly maintains his code by adding extra requirement like how his solution handles revoking access, handles new server instance.
Good Luck.
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What Is The Difference Between Append And Extend Methods
Both append and extend methods are methods used to add elements at the end of a list.
- append: Adds the given element at the end of the list that called this append method
- extend: Adds the elements of another list at the end of the list that called this extend method
For in-depth knowledge, check out our Python Tutorial and boost your Python skills!
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How Are Arguments Passed By Value Or By Reference In Python
- Pass by value: Copy of the actual object is passed. Changing the value of the copy of the object will not change the value of the original object.
- Pass by reference: Reference to the actual object is passed. Changing the value of the new object will change the value of the original object.
In Python, arguments are passed by reference, i.e., reference to the actual object is passed.
defappendNumber: arr.appendarr = print #Output: => appendNumberprint #Output: =>
What Do You Mean By Python Literals
Literals refer to the data which will be provided to a given in a variable or constant.
Literals supported by python are listed below:
String Literals
These literals are formed by enclosing text in the single or double quotes.
For Example:
Boolean literals help to denote boolean values. It contains either True or False.
x=True
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What Are The Differences Between Pickling And Unpickling
Pickling is the conversion of python objects to binary form. Whereas, unpickling is the conversion of binary form data to python objects. The pickled objects are used for storing in disks or external memory locations. Unpickled objects are used for getting the data back as python objects upon which processing can be done in python.
Python provides a pickle module for achieving this. Pickling uses the pickle.dump method to dump python objects into disks. Unpickling uses the pickle.load method to get back the data as python objects.
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A few of the best DevOps interview questions include
What is continuous integration and how would you implement it?
- In short, it is a development process where code is integrated directly within the deployment process.
- The software is built, tested, and deployed automatically by various tools. Travis CI, Jenkins, Codeship, and Circle CI are a few that come to mind. Each has their pros and cons, but most are set out to do the same thing.
What is your process for deployment?
- This can be a very long answer or short. The process starts with understanding the needs of the software in question to deploy. There may be some requirements specific to the build, ie. Node project will need Node, package manager, and other dependencies.
- Understanding what type of continuous integration also whether to use a container like Docker.
- What backing up data looks like. Database is important to have redundancy.
- What kind of machine youll be running on Linux, Ubuntu, Windows.
- If its a web app what type of web server youll be running Apache2, Nginx, etc.
- How you plan on configuring the web server.
- Implement SSH, and or rewrite rules.
- Caching options, caching proxy like CloudFlare.
- Monitoring of server for downtime or errors.
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How Will You Approach A Project That Needs To Implement Devops
The following standard approaches can be used to implement DevOps in a specific project:
Stage 1
An assessment of the existing process and implementation for about two to three weeks to identify areas of improvement so that the team can create a road map for the implementation.
Stage 2
Create a proof of concept . Once it is accepted and approved, the team can start on the actual implementation and roll-out of the project plan.
Stage 3
The project is now ready for implementing DevOps by using version control/integration/testing/deployment/delivery and monitoring followed step by step.
By following the proper steps for version control, integration, testing, deployment, delivery, and monitoring, the project is now ready for DevOps implementation.
Q66 Explain Inheritance In Python With An Example
Ans: Inheritance allows One class to gain all the members of another class. Inheritance provides code reusability, makes it easier to create and maintain an application. The class from which we are inheriting is called super-class and the class that is inherited is called a derived / child class.
They are different types of inheritance supported by Python:
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