How to remove a key from a dictionary in Julia

A dictionary is a data structure that stores data values in key-value pairs. They are also referred to as a map, a hash, or a HashMap. For example, we have data on students with their respective scores for a course and you are looking for a way to represent it. We would most likely represent it as a dictionary where the key would be the name of the student and the value would be the student's scores.

This representation gives us the leverage to make corrections to our data in case some information changes, such as changing the score of a particular student, changing a student's name, etc.

In this Answer, we're going to take a look at the ways in which we can remove a key from a dictionary in Julia.

Ways of removing keys from a dictionary

There are different ways in which we can remove keys from a dictionary in Julia. Some of which are:

  • Using the delete! method

  • Using the pop! method

Let's see how to use both methods.

The delete! method

Let's see how to use the delete! method to delete a key from a dictionary:

School = Dict("Mark" => 45, "Jane" => 70, "Peter" => 88)
delete!(School,"Jane")
println(School)

Explanation

  • Line 1: Create an untyped dictionary named as School that has three key-value pairs.

  • Line 2: Remove the the key Jane from the dictionary School.

  • Line 3: Print the dictionary.

Note: When we delete the key, we also delete the value.

The pop! method

Here, we are going to remove same dictionary but we are going to be removing "Mark" from the dictionary by using pop! method.

School = Dict("Mark" => 45, "Jane" => 70, "Peter" => 88)
pop!(School,"Mark")
println(School)

Explanation

  • Line 1: Create a dictionary named as School.

  • Line 2: Remove the the key Mark from the dictionary School.

  • Line 3: Print the dictionary.

We have seen that the key with the value has been removed from the dictionary School where key equals Mark.

Conclusion

In this Answer, we have learned how to remove keys from a dictionary in Julia.

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