Apply operations on a collection in Julia – map() and map!() Methods

The map() is an inbuilt function in julia which is used to transform the specified collection by using specified operation to each element.

Syntax: map(f, c…)

Parameters:

• f: Specified operation.
• c: Specified collection.

Returns: It returns the transformed elements.

Example:

# Julia program to illustrate
# the use of map() method

# Getting the transformed elements.
println(map(x -> x * 2, [5, 10, 15]))
println(map(+, [1, 2, 3], [10, 20, 30]))
println(map(x -> x / 5, [5, 10, 15]))
println(map(-, [10, 20, 30], [1, 2, 3]))

Output:

[10, 20, 30]
[11, 22, 33]
[1.0, 2.0, 3.0]
[9, 18, 27]

map!()

The map!() is an inbuilt function in julia. This function is same as map() function but stores the result in destination rather than a new collection. The destination must be at least as large as the first collection.

Syntax:
map!(function, destination, collection…)

Parameters:

• function: Specified operation.
• destination: The destination where the result get stored.
• collection: Specified collection.

Returns: It returns the transformed elements.

Example:

# Julia program to illustrate
# the use of map !() method

# Getting the transformed elements.
a = zeros(3);
map !(x -> x * 3, a, [1, 2, 3]);
println(a)

b = ones(3);
map !(x -> x / 3, b, [3, 6, 9]);
println(b)

Output:

[3.0, 6.0, 9.0]
[1.0, 2.0, 3.0]