Keyword Arguments

Intermediate Julia

Anthony Markham

Quantitative Developer

Keyword arguments - overview

Assigns a keyword to a function parameter.
When passing an argument into a function we use the assigned keyword.
We can mix keyword arguments with other types, but keyword arguments must come last.

function person(; location)
    return location
end

Keyword arguments - syntax

Use the semicolon ; operator to denote keyword arguments.

function person(; location)
    return location
end

person(location="Sydney")

"Sydney"

Keyword arguments - mixing argument types

Remember, positional arguments need to be before keyword arguments.

function person(name, ; location)
    return name, location
end

person("Anthony", location="Sydney")

("Anthony", "Sydney")

Variable number of arguments

Variable number of arguments (varargs) allows us to pass an arbitrary number of arguments.
Use the ellipsis ... operator to mark a parameter as accepting varargs.

function names(name...)
    println(name)
end

names("Anthony", "Ben", "Hannah", "Julia")

("Anthony", "Ben", "Hannah", "Julia")

Variable number of argument types

We can mix positional, keyword, and varargs all together in a function definition.

function person(name, education... ; location)
    return name, education, location
end

anthony = person("Anthony", "BE", "BS", "MComm", location="Sydney")

("Anthony", ("BE", "BS", "MComm"), "Sydney")

println(anthony[2][1])

BE

Let's practice!

Intermediate Julia