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Elixir DateTime is a programming language module that deals with date and time manipulation. It was introduced as part of the Elixir programming language, which was first released in 2011 by José Valim, a former member of the Ruby on Rails core team. The DateTime module provides functions for creating, converting and manipulating dates and times in various formats. Its robustness makes it an essential tool for developers working on applications where precise timekeeping is crucial. Information about this can be found in Elixir's official documentation.

Ask the right questions secure the right Elixir DateTime talent among an increasingly shrinking pool of talent.

First 20 minutes

General Elixir DateTime app knowledge and experience

The first 20 minutes of the interview should seek to understand the candidate's general background in Elixir DateTime application development, including their experience with various programming languages, databases, and their approach to designing scalable and maintainable systems.

What is the primary use of Elixir DateTime?

Elixir DateTime is primarily used for handling dates and times in the Elixir programming language. It provides functionality for parsing, formatting, manipulating, and comparing dates and times.

How would you create a new DateTime instance in Elixir?

You can create a new DateTime instance in Elixir using the DateTime.new/2 function, providing it with the year, month, day, hour, minute, second, and microsecond values.

What are the key components of a DateTime struct in Elixir?

The key components of a DateTime struct in Elixir are: year, month, day, hour, minute, second, microsecond, timezone_info, and utc_offset.

Describe the difference between DateTime.utc_now/0 and DateTime.local_now/0 in Elixir.

DateTime.utc_now/0 returns the current date and time in UTC while DateTime.local_now/0 returns the current date and time in the local timezone of the system.

How would you convert a DateTime struct to a string in Elixir?

You can convert a DateTime struct to a string in Elixir using the DateTime.to_string/1 function.

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What you’re looking for early on

Does the candidate have a solid understanding of Elixir and its DateTime module?

Has the candidate demonstrated the ability to problem solve and debug within the Elixir environment?

Can the candidate effectively communicate their thought process and reasoning?

Does the candidate have experience with test-driven development in Elixir?

Next 20 minutes

Specific Elixir DateTime development questions

The next 20 minutes of the interview should focus on the candidate's expertise with specific backend frameworks, their understanding of RESTful APIs, and their experience in handling data storage and retrieval efficiently.

What are the differences between DateTime.add/3 and DateTime.diff/2 functions in Elixir?

DateTime.add/3 function adds a specified number of units to a DateTime struct while DateTime.diff/2 function computes the difference between two DateTime structs.

Describe the difference between DateTime.compare/2 and DateTime.equal?/2 in Elixir.

DateTime.compare/2 compares two DateTime structs and returns :lt, :eq, or :gt while DateTime.equal?/2 checks if two DateTime structs are equal and returns true or false.

How would you parse a string into a DateTime struct in Elixir?

You can parse a string into a DateTime struct in Elixir using the DateTime.from_iso8601/1 function.

What are the differences between DateTime.shift_zone/2 and DateTime.to_time/1 functions in Elixir?

DateTime.shift_zone/2 function changes the timezone of a DateTime struct while DateTime.to_time/1 function converts a DateTime struct to a Time struct.

Describe the difference between DateTime.to_date/1 and DateTime.to_naive/1 in Elixir.

DateTime.to_date/1 converts a DateTime struct to a Date struct while DateTime.to_naive/1 converts a DateTime struct to a NaiveDateTime struct.

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At this point, a skilled Elixir DateTime engineer should demonstrate strong problem-solving abilities, proficiency in Elixir DateTime programming language, and knowledge of software development methodologies. Red flags include lack of hands-on experience, inability to articulate complex concepts, or unfamiliarity with standard coding practices.

Digging deeper

Code questions

These will help you see the candidate's real-world development capabilities with Elixir DateTime.

What does this Elixir code do: DateTime.utc_now()?
DateTime.utc_now()
This code returns the current date and time in UTC.
What will be the output of this Elixir code: DateTime.to_string(~U[2022-02-28T15:30:28Z])?
DateTime.to_string(~U[2022-02-28T15:30:28Z])
This code will output the string representation of the given DateTime, which is '2022-02-28 15:30:28Z'.
What does this Elixir code do: Enum.map([~U[2022-02-28T15:30:28Z], ~U[2022-02-27T14:20:18Z]], fn dt -> DateTime.to_string(dt) end)?
Enum.map([~U[2022-02-28T15:30:28Z], ~U[2022-02-27T14:20:18Z]], fn dt -> DateTime.to_string(dt) end)
This code converts each DateTime in the list to its string representation.
What does this Elixir code do: Task.async(fn -> DateTime.utc_now() end)
Task.async(fn -> DateTime.utc_now() end)
This code starts a new process and runs the function asynchronously, which returns the current date and time in UTC.

Wrap-up questions

Final candidate for Elixir DateTime Developer role questions

The final few questions should evaluate the candidate's teamwork, communication, and problem-solving skills. Additionally, assess their knowledge of microservices architecture, serverless computing, and how they handle Elixir DateTime application deployments. Inquire about their experience in handling system failures and their approach to debugging and troubleshooting.

How would you truncate a DateTime struct to a specified precision in Elixir?

You can truncate a DateTime struct to a specified precision in Elixir using the DateTime.truncate/2 function.

What are the differences between DateTime.utc_now/0 and DateTime.local_now/0 functions in Elixir?

DateTime.utc_now/0 function returns the current date and time in UTC while DateTime.local_now/0 function returns the current date and time in the local timezone of the system.

Describe the difference between the use of DateTime.utc_now/0 and DateTime.now/1 in Elixir.

DateTime.utc_now/0 returns the current date and time in UTC. DateTime.now/1 returns the current date and time in the timezone provided as an argument.

Elixir DateTime application related

Product Perfect's Elixir DateTime development capabilities

Beyond hiring for your Elixir DateTime engineering team, you may be in the market for additional help. Product Perfect provides seasoned expertise in Elixir DateTime projects, and can engage in multiple capacities.

Elixir DateTime Consultive assessments

Elixir DateTime Application Conversion Assessment Elixir DateTime Application Integration Assessment Elixir DateTime Data & Database Integration Assessment

Custom Elixir DateTime development projects

Custom Elixir DateTime App Conversion Elixir DateTime Custom App Development Process App UI Design for Elixir DateTime Facelifts

Hiring guide for Elixir DateTime Engineers

Elixir DateTime Developer Hiring Guide

What you’re looking for early on

The ideal back-end app developer

What you’re looking to see on the Elixir DateTime engineer at this point.

Elixir DateTime Consultive assessments

Custom Elixir DateTime development projects