Skip to content

Core Array Functions

Alex Gravenor edited this page Aug 19, 2018 · 23 revisions

Updated as of blz v2.6

Core Array Functions

blz-ospl\Packages\Core\ArrayUtil.blz

Function Arguments
concatenate array
contains? element
copy
each method
filter method
fold_left accumulator, method
fold_right accumulator, method
length
map method
nil?
remove index
reverse
sample
show
shuffle
size
slice start_index, end_index
sort
to_json
to_string
unique

Concatenate

concatenate(arr) - Returns the resulting concatenation of two arrays.

Example:

my_arr_A = [0, 1, 2]
my_arr_B = [3, 4, 5]
my_arr_AB = my_arr_A.concatenate(my_arr_B)
print("my_arr_AB: " + my_arr_AB)

Output:

my_arr_AB: [0, 1, 2, 3, 4, 5]

Contains

contains?(element) - Returns true if the element is contained in the array and false otherwise.

Example:

my_arr = [1, 2]
print(arr.contains?(1))

Output:

true

Copy Array Contents

copy() - Returns a copy of the array.

Example:

my_arr = [0, 1, 2]
my_arr_copy = my_arr.copy()
print(my_arr_copy)

Output:

[0, 1, 2]

Each

each(method) - Takes a method and performs it on each element in the array.

Example:

my_arr = ["apple", "peach", "cherry"]
my_arr.each(print)

Output:

apple
peach
cherry

Empty

empty?() - Returns true if the array is empty.

Example:

my_arr = []
print(my_arr.empty?())

my_arr2 = [1]
print(my_arr2.empty?())

Output:

true
false

Filter

filter(method) - Selects the elements of the array that produce true when passed to the method

Example:

:is_even?(number)
    return number % 2 == 0
end

:main
   arr = [1,2,3,4,5,6,7]
   print(arr.filter(is_even?))
end

Output:

[2, 4, 6]

Fold Left

fold_left(accumulator, method) - Collapses the array using the method with the accumulator and elements as parameters, from left to right.

Example:

:add(a, b)   #method returns the sum of a and b
    return a + b
end

my_arr = [1, 2, 3, 4, 5]
print(arr.fold_left(0, add))

print(arr.fold_left(5, add))

Output:

15
20

Fold Right

fold_right(accumulator, method) - Collapses the array using the method with the accumulator and elements as parameters, from right to left.

Example:

:add(a, b)     #method returns the sum of a and b
    return a + b
end

arr = [1, 2, 3, 4, 5]
print(arr.fold_right(0, add))

print(arr.fold_right(5, add))

Output:

15
20

Length

length() - Returns the length of the array.

Example:

my_arr = [0, 1, 2, 3]
len = my_arr.length()
print("my_arr length: " + len)

Output:

my_arr length: 4

Map

map(method) - Calls method on each element in the array.

Example:

my_arr = ["apple", "peach", "cherry"]
my_arr.map(print)

my_arr.map!(sort)
print(my_arr)

Output:

apple
peach
cherry
[aelpp, acehp, cehrry]

Nil?

nil?() - Is this array nil? (spoilers no)

Example:

print([1].nil?())

Output:

false

Remove

remove(index) - Removes the element at the index from the array.

Example:

my_arr = [0, 1, 2, 3, 4, 5, 6]
print("before remove: " + arr)
my_arr.remove!(3)
print("after removing index 3: " + my_arr)
my_arr.remove!(5)
print("after removing index 5: " + my_arr)
my_arr.remove!(0)
print("after removing index 0: " + my_arr)
arr2 = my_arr.remove(1)
print("arr2 makes a copy of my_arr and removes index 1: " + arr2)

Output:

before remove: [0, 1, 2, 3, 4, 5, 6]
after removing index 3: [0, 1, 2, 4, 5, 6]
after removing index 5: [0, 1, 2, 4, 5]
after removing index 0: [1, 2, 4, 5]
arr2 makes a copy of my_arr and removes index 1: [1, 4, 5]

Reverse Array Order

reverse() - Reverses the order of elements in the array.

Example:

my_arr = [0, 1, 2, 3]
my_arr = my_arr.reverse()
print(my_arr)

Output:

[3, 2, 1, 0]

Sample From Array

sample() - Returns a random entry in the array

Example:

arr = [1, 2, 3, "a", "b", "c"]
print(arr.sample())
print(arr.sample())

Sample Output:

a
2

Show

show() - Returns a string representation of the string

Example:

arr = [1, 2, "a", "b"]
print(arr.show())

Output:

[1, 2, a, b]

Shuffle Array Contents

shuffle() - Shuffles the contents of the array.

Example:

my_arr = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
my_arr = my_arr.shuffle()
new_arr = my_arr.shuffle()         # will be my_arr shuffled again.
print("my_arr: " + my_arr)
print("new_arr: " + new_arr)

Output:

my_arr: [9, 3, 2, 1, 0, 6, 5, 7, 4, 8]
new_arr: [1, 2, 9, 6, 8, 3, 7, 4, 0, 5]

Size

size() - Returns the size of the array.

Example:

my_arr = [0, 1, 2, 3]
len = my_arr.size()
print("my_arr length: " + len)

Output:

my_arr length: 4

Slice

slice(start, end) - Returns a slice of the array indexed from start to, but not including, end.

Example:

my_arr = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
new_arr_1 = my_arr.slice(4, 8)                     # a sub-array
new_arr_2 = my_arr.slice(0, array_length(my_arr))  # the entire array
new_arr_3 = my_arr.slice(0, 0)                     # none of the array
print("new_arr_1: " + new_arr_1)
print("new_arr_2: " + new_arr_2)
print("new_arr_3: " + new_arr_3)

Output:

new_arr_1: [4, 5, 6, 7]
new_arr_2: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
new_arr_3: []

Sort by Ascending Order

sort() - Sorts the array in ascending order.

Example:

my_arr = [9, 3, 2, 1, 0, 6, 5, 7, 4, 8]
my_arr = my_arr.sort()
print(my_arr)

Output:

[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

To String

to_string() - Return the array as a string.

Example:

my_arr = [1, 2, 3, 4]
print(my_arr.to_string())

Output:

[1, 2, 3, 4]    # this is equivalent to the string "[1, 2, 3, 4]"

To JSON

to_json() - Returns a string that is a JSON representation of the array

Example:

arr = [1, 2, "a", "b"]
print(arr.to_json())

Output:

[1, 2, "a", "b"]

Unique

unique() - Returns a copy of the array with duplicate elements removed.

Example:

my_arr = [1, 2, 2, 3, 3, 3, 4, 4, 4, 4]
my_arr = my_arr.unique()
print(my_arr)

my_arr = [2, 9, 2, 9, 9, 6, 4, 5, 9, 4, 3, 4, 6, 1, 5, 3, 4, 7, 5, 7, 8, 3]
my_arr = my_arr.unique()
print(my_arr)

Output:

[1, 2, 3, 4]
[2, 9, 6, 4, 5, 3, 1, 7, 8]
You can’t perform that action at this time.