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Elixir Keyword Lists is a feature of the Elixir programming language, which was developed by José Valim in 2011. It allows developers to create lists of tuples where the first item is an atom, enhancing readability and organization in code. This feature is particularly useful for passing optional values to functions. The Elixir language, including its Keyword Lists feature, was influenced by Ruby, Erlang, and Clojure languages. Information about Elixir and its features can be found on the official Elixir language website and in various programming resources such as "Programming Elixir" by Dave Thomas.

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

First 20 minutes

General Elixir Keyword Lists app knowledge and experience

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

How would you define a Keyword List in Elixir?

A Keyword List in Elixir is a list of tuples where the first item of the tuple is an atom. It is defined as: keyword_list = [{:key, 'value'}, {:another_key, 'another_value'}].

What are the main uses of Keyword Lists in Elixir?

Keyword Lists in Elixir are mainly used for passing optional values, or when the order of keys is important. They are also used in pattern matching.

Describe the difference between Keyword Lists and Maps in Elixir.

The main difference between Keyword Lists and Maps in Elixir is that Keyword Lists allow for duplicate keys and preserve the order of elements, while Maps do not allow for duplicate keys and do not preserve order.

How would you access a value from a Keyword List in Elixir?

You can access a value from a Keyword List in Elixir using the list name followed by the key in square brackets, like this: keyword_list[:key].

What happens when you try to access a key that does not exist in a Keyword List?

When you try to access a key that does not exist in a Keyword List, Elixir will return nil.

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What you’re looking for early on

Does the candidate possess a deep understanding of Elixir language and its syntax?

How well does the candidate understand Keyword Lists in Elixir?

Can the candidate demonstrate problem-solving skills, especially in relation to Elixir and Keyword Lists?

Does the candidate have experience with testing in Elixir?

Next 20 minutes

Specific Elixir Keyword Lists 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.

How would you update a value in a Keyword List in Elixir?

You can update a value in a Keyword List in Elixir using the put/3 function, like this: keyword_list = Keyword.put(keyword_list, :key, 'new_value').

What are the performance characteristics of Keyword Lists in Elixir?

Keyword Lists in Elixir have a linear performance characteristic. This means that operations like accessing, updating, or deleting a value take time proportional to the size of the list.

How would you delete a key-value pair from a Keyword List in Elixir?

You can delete a key-value pair from a Keyword List in Elixir using the delete/2 function, like this: keyword_list = Keyword.delete(keyword_list, :key).

What happens when you have duplicate keys in a Keyword List in Elixir?

When you have duplicate keys in a Keyword List in Elixir, the last one defined will be used when accessing the value, but all will be kept in the list.

How would you convert a Keyword List to a Map in Elixir?

You can convert a Keyword List to a Map in Elixir using the Map.new/1 function, like this: map = Map.new(keyword_list).

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At this point, a skilled Elixir Keyword Lists engineer should demonstrate strong problem-solving abilities, proficiency in Elixir Keyword Lists 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 Keyword Lists.

What does this simple Elixir Keyword List declaration do?
list = [foo: 1, bar: 2, foo: 3]
This declares a Keyword List with three elements. Note that keys are not unique, so there can be multiple entries for the same key.
What is the output of this Keyword List access operation?
list = [foo: 1, bar: 2, foo: 3]
IO.puts Keyword.get(list, :foo)
This will print '1' to the console. Keyword.get/2 fetches the first value associated with the key :foo from the Keyword List.
What does this Keyword List manipulation operation do?
list = [foo: 1, bar: 2, foo: 3]
list = Keyword.put(list, :bar, 20)
This operation replaces the first occurrence of the key :bar in the Keyword List with the value 20. The new list will be [foo: 1, bar: 20, foo: 3].
What does this Keyword List concurrency-related operation do?
list = [foo: 1, bar: 2, foo: 3]
Task.async(fn -> Keyword.put(list, :bar, 20) end)
This operation spawns a new process that executes the function in parallel. The function replaces the first occurrence of the key :bar in the Keyword List with the value 20.

Wrap-up questions

Final candidate for Elixir Keyword Lists 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 Keyword Lists application deployments. Inquire about their experience in handling system failures and their approach to debugging and troubleshooting.

How would you merge two Keyword Lists in Elixir?

You can merge two Keyword Lists in Elixir using the ++ operator, like this: merged_list = list1 ++ list2.

What is the difference between Keyword Lists and Dictionaries in Elixir?

The main difference between Keyword Lists and Dictionaries in Elixir is that Keyword Lists allow for duplicate keys and preserve the order of elements, while Dictionaries do not allow for duplicate keys and do not preserve order.

How would you check if a key exists in a Keyword List in Elixir?

You can check if a key exists in a Keyword List in Elixir using the has_key?/2 function, like this: Keyword.has_key?(keyword_list, :key).

Elixir Keyword Lists application related

Product Perfect's Elixir Keyword Lists development capabilities

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

Elixir Keyword Lists Consultive assessments

Elixir Keyword Lists Application Conversion Assessment Elixir Keyword Lists Application Integration Assessment Elixir Keyword Lists Data & Database Integration Assessment

Custom Elixir Keyword Lists development projects

Custom Elixir Keyword Lists App Conversion Elixir Keyword Lists Custom App Development Process App UI Design for Elixir Keyword Lists Facelifts

Hiring guide for Elixir Keyword Lists Engineers

Elixir Keyword Lists 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 Keyword Lists engineer at this point.

Elixir Keyword Lists Consultive assessments

Custom Elixir Keyword Lists development projects