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Python Coding Interview Questions For Data Engineers

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What Is The Difference Between A List And A Tuple

Top 15 Python Interview Questions | Python Interview Questions And Answers | Intellipaat

Both a list and a tuple are a collection of items. The main difference between list objects and tuple objects is mutability. While you can make changes to a list, a tuple contains immutable objects that cannot be altered. This generally makes a tuple a faster option that doesnt use as much memory as a list. Another major difference is in how you define a list vs a tuple. When defining a tuple, you will use a pair of parentheses. When defining a list, you will use a pair of square brackets.

A similarity that these two collection data types have in common is that they are both a sequence data type that can store a wide range of objects.

What Data Security Solutions Does Azure Sql Db Provide

In Azure SQL DB, there are several data security options:

  • Azure SQL Firewall Rules: There are two levels of security available in Azure.

  • The first are server-level firewall rules, which are present in the SQL Master database and specify which Azure database servers are accessible.

  • The second type of firewall rule is database-level firewall rules, which monitor database access.

  • Azure SQL Database Auditing: The SQL Database service in Azure offers auditing features. It allows you to define the audit policy at the database server or database level.

  • Azure SQL Transparent Data Encryption: TDE encrypts and decrypts databases and performs backups and transactions on log files in real-time.

  • Azure SQL Always Encrypted: This feature safeguards sensitive data in the Azure SQL database, such as credit card details.

What Is Meant By Sql Injection

SQL injection is a type of vulnerability in SQL codes that allows attackers to control back-end database operations and access, retrieve and/or destroy sensitive data present in databases. SQL injection involves inserting malicious SQL code into a database entry field. When the code gets executed, the database becomes vulnerable to attack, and SQL injection is also known as SQLi attack.

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Can You Explain What A List And Dict Comprehension Is

Both a list comprehension and a dict comprehension are single-line syntactic constructs that allow for efficient use of code to accomplish complex tasks. This is a much quicker way than many conditional statements, like for and if loops. They are examples of some of the many special functions that Python offers that can make processes simpler. An example of a dict comprehension can be seen in this list of prices in a list being changed from US Dollars to British Pounds.

As you can see, the new dictionary has been updated to reflect the items for the last dictionary with a slight modification made. This method is fairly lightweight and doesnt require any complex programming to accomplish a simple task.

For an example of list comprehension, we can modify items in a list without the use of conditional statements.

Instead of a loop, we can carry the values over to a new list with the necessary modifications made.

Both of these options lower the amount of time per iteration and make more efficient use of memory. The for loop may take up more memory than the method that didnt utilize a loop. However, they are both proper syntax that will return the right result and are usually used for the same purpose, just in different contexts.

Access Common String Groups With String Constants

Read Mastering Python: Machine Learning, Data Structures, Django ...

Its trivia time! Is A> a true or false?

Its false, because the ASCII code for A is 65, but a is 97, and 65 is not greater than 97.

Why does the answer matter? Because if you want to check if a character is part of the English alphabet, one popular way is to see if its between A and z .

Checking the ASCII code works but is clumsy and easy to mess up in coding interviews, especially if you cant remember whether lowercase or uppercase ASCII characters come first. Its much easier to use the constants defined as part of the string module.

You can see one in use in is_upper, which returns whether all characters in a string are uppercase letters:

> > >   importstring> > >   defis_upper:... forletterinword:... ifletternotinstring.ascii_uppercase:... returnFalse... returnTrue...> > >   is_upperFalse> > >   is_upperTrue

is_upper iterates over the letters in word, and checks if the letters are part of string.ascii_uppercase. If you print out string.ascii_uppercase youll see that its just a lowly string. The value is set to the literal ABCDEFGHIJKLMNOPQRSTUVWXYZ.

All string constants are just strings of frequently referenced string values. They include the following:

  • string.ascii_letters

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Mention Some Differences Between The Delete And Truncate Statements In Sql

DELETE command

TRUNCATE command

The DELETE command helps to delete one specific row or more than one row corresponding to a certain condition.

The TRUNCATE command helps to delete all rows of a table.

It is a Data Manipulation Language command.

It is a Data Definition Language command.

In the case of the DELETE statement, rows are removed one at a time. The DELETE statement records an entry for each deleted row in the transaction log.

Truncating a table removes the data associated with a table by deallocating the data pages that store the table data. Only the page deallocations get stored in the transaction log.

The DELETE command is slower than the TRUNCATE command.

The TRUNCATE command is faster than the DELETE command.

You can only use the DELETE statement with DELETE permission for the table.

Using the TRUNCATE command requires ALTER permission for the table.

Top 49 Python Interview Questions In 2022

Kyle Herrity is a seasoned software engineer with over 15 year of industry experience, ranging from high-level applications development to low-level embedded systems projects.

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Jenn, a career coach, provides a look at the interviewing process and shares tips on how to position yourself for success at every step.

Many computer programming careers require the employee to be fluent in one or more programming languages. One of the most common languages in use today is Python. Anyone interested in a job that uses Python will need to answer questions about the language in their job interview.

One of the best ways to prepare for a Python interview is to study common questions and answers. In this article, we discuss the typical structure of a Python interview, technical and general questions you might be asked and how to answer them.

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What Are The Roles And Responsibilities Of Data Engineer

Some of the roles and responsibilities of a data engineer are

  • Create and implement ETL data pipeline for a variety of clients in various sectors.

  • Generate accurate and useful data-driven solutions using data modeling and data warehousing techniques.

  • Interact with other teams and help them by delivering relevant datasets for analysis.

  • Build data pipelines for extraction and storage tasks by employing a range of big data engineering tools and various cloud service platforms.

What According To You Are The Daily Responsibilities Of A Data Engineer

Solving Real-World Data Science Interview Questions! (with Python Pandas)

There is no absolute answer here, but you can share the experience of your last job and your responsibilities as an engineer. The job description is also a good place to look for this information.

However, in general, the daily responsibilities of data engineers include:

  • Development, testing, and maintaining databases
  • Developing data solutions based on business requirements
  • Data acquisition
  • Developing, validating, and maintaining data pipelines for ETL, and data modeling, transformation, and serving.
  • In some cases, deploying statistical models.
  • Maintaining data quality by cleaning, validating, and monitoring the data stream.
  • Improving system reliability, performance, and quality.
  • Following data governance and security guidelines to perform each task.

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When Do You Use Pass Continue And Break

The break statement in Python terminates a loop or another statement containing the break statement. If a break statement is present in a nested loop, it will terminate only the loop in which it is present. Control will pass the statements after the break statement if they are present.

The continue statement forces control to stop the current iteration of the loop and execute the next iteration rather than terminating the loop completely. If a continue statement is present within a loop, it leads to skipping the code following it for that iteration, and the next iteration gets executed.

Pass statement in Python does nothing when it executes, and it is useful when a statement is syntactically required but has no command or code execution. The pass statement can write empty loops and empty control statements, functions, and classes.

Do We Need To Master Python For Machine Learning

Yes, it is important to master Python if you want to pursue a career in machine learning. Python is one of the most popular programming languages used in the field of machine learning and is the language of choice for many AI and data science projects. With Python, you can easily build complex machine learning models, including deep learning networks and natural language processing systems. Additionally, Pythons library of machine learning packages makes it easy to quickly get up and running with projects. By mastering Python, you can create powerful machine learning models that can be used to solve real-world problems.

Python is the most popular language for machine learning due to its extensive library base for AI and ML. Data scientists and machine learning engineers can quickly and efficiently create efficient and accurate models using libraries such as Keras, TensorFlow, and Scikit-learn. Python is a great learning tool for those just starting out in Machine Learning because of its simple to understand syntax, making it simple to get started. Those who want to learn Machine Learning can progress to other languages such as R, Scala, or others after a few months of practice and familiarization. Python, which includes a plethora of powerful libraries and syntax that is highly accessible, is the ideal language for those who want to learn machine learning first hand.

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Explain The Difference Between Pickling And Unpickling

Pickling is the process of converting the hierarchy of Python objects into a byte stream, and then into a Python file as a string representation. Unpickling is the opposite of this process. Python programs run from source code files and are directly interpreted by the byte code. Once the virtual machine begins to move the objects from a specific program to the computer, the pickle module carries out a process of serialization of those objects into an understandable language that the computer can store through a dump function.

This dump functions primary function is to convert the program to a Python file. Then, when a computers Python source code files begin to convert back, the unpickling process starts. This reverse process is also accomplished through the pickle module, when the executable code is converted back and the string representations are turned back into the original Python object.

What Are Freeze Panes In Ms Excel

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Freeze panes are used in MS Excel to lock a particular row or column. The rows or columns you lock will be visible on the screen even when scrolling the sheet horizontally or vertically.

To freeze panes on Excel:

  • First, select the cell to the right of the columns and below the rows to be kept visible.

  • Select View > Freeze Panes > Freeze Panes.

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    What Are The Design Schemas Of Data Modeling

    Design schemas are fundamental to data engineering, so try to be accurate while explaining the concepts in everyday language. There are two schemas: star schema and snowflake schema.

    Star schema has a fact table that has several associated dimension tables, so it looks like a star and is the simplest type of data warehouse schema. Snowflake schema is an extension of a star schema and adds additional dimension tables that split the data up, flowing out like a snowflakeâs spokes.

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    What Are Some Examples Of Inheritance In Python What Does Inheritance Do

    If an engineer wanted to enable one class to get every member from another class, they could do this with inheritance. Candidates might also mention the advantages of inheritance, which enables engineers to reuse code with very little difficulty as far as application maintenance is concerned, before describing the main types of inheritance:

    • Multiple inheritances, in which one derived class gets inherited from several base classes
    • Hierarchical inheritance, in which its possible to inherit several child classes from a single base class
    • Single inheritance, in which a single derived class inherits from one superclass

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    What Do You Mean By Blocks And Block Scanner

    Block is the smallest unit of a data file and is regarded as a single entity. When Hadoop comes across a large data file, it automatically breaks it up into smaller pieces called blocks.

    A block scanner is implemented to check whether the loss-of-blocks generated by Hadoop are successfully installed on the DataNode.

    What Challenges Did You Face In Your Recent Project And How Did You Overcome Them

    python coding data science interview questions and answers software engineer questions and answers

    With this question, the panel generally wants to know your problem-solving ability and how well you perform under pressure. To answer the question, first, brief them about the situations that lead to the problem. You should tell them about your role in that situation. For example, if you played a leading role in solving that problem, that would tell the interviewer about competency as a leader. After that tell them about the action you took to solve the problem. To end the answer on a positive note, you should tell them about the consequences of the challenge and the learning you took out of it.

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    Which Approach Would You Use To Get Rid Of White Spaces From Python Strings

    This question is frequently asked in Python technical interviews to help interviewers understand their candidates technical understanding of Python functions. Good answers will mention that the Python String strip function can get rid of white spaces from Python strings.

    Candidates might go a step further and mention that lstrip or rstrip can be used to get rid of leading or trailing white spaces.

    Is Python A Good Language For Beginners

    Python programming is used in the backend, and it is one of the top languages for beginners to learn and implement. It is very similar to Ruby. However, it requires comparatively less effort in coding. This language is easily approachable, and you are not required to know or have skills in any other programming language to learn this.

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    Understanding The Data Engineer Interview Process

    You should know the basic interview pattern to frame a strategic tech interview prep plan accordingly. A typical data engineer interview at top technical companies includes:

    • The initial HR screen round includes basic questions around your experience, interest in the role, and the requirements of the role.
    • The technical phone screen will include a couple of behavioral questions and coding questions. The coding questions focus on data structures, mostly on arrays, trees, sorting, or linked lists.
    • The on-site interview will have three to four rounds that include: 1. A round based on Python, SQL, and big data frameworks2. Two to three rounds on core data engineering concepts3. A behavioral interview round

    You can learn in detail about the data engineer interview process in FAANG+ companies here.

    What Is The Difference Between Append And Extend Methods

    Articles  Python For Engineers

    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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    Python Data Engineer Interview Question #: Ranking Hosts By Bed

    Link to the question:

    Question:

    There is one table provided to solve this question. In this question, we need to rank hosts based on the number of beds they have listed. One host might have multiple listings. Also, some hosts might have the same number of beds so the rank for them should be the same. Please have a look at the sample output from the table provided:

    airbnb_apartments

    Approach:

    As a first step we need to find the total number of beds listed by each host. The question mentions that one host might have multiple properties listed, thus, we need to add the number of beds by each host by using a groupby function in python and then convert the result into the data frame

    # Import your librariesimport pandas as pd# Start writing coderesult = airbnb_apartments.groupby.sum.to_frame.reset_index

    Next step is to rank the hosts based on the number of beds listed by them. We already have the host and the number of beds columns calculated in the previous steps. Letâs use the rank function with the Dense method since we need to provide the same rank to the hosts which have the same number of beds listed on the website.

    result = result.rank

    Lastly, we need to sort the data based on the rank in ascending order. Letâs use sort_values to sort the data in the ascending order of the rank for each host.

    result = result.sort_values

    Final Code:

    Code Output:

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