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An array is a collection of values, stored contiguously.
📦 Node.js, 🌐 Web, 📜 Files, 📰 Docs, 📘 Wiki.

This package includes comprehensive set of array functions with which you can generate an array, clone it, query about it, get non-negative indices, manage its length, get/set elements, fully or partially sort it, obtain minimum(s)/maximum(s), compare it with another array, get a part of it, search a value, obtain all possible arrangements or random arrangements, find an element, take/drop elements or scan from its beginning or its end, search the index of a part of it, perform functional operations, flatten multi-level arrays, obtain prefix sum, manipulate it in various ways, count/partition elements, split it, concatenate/join multiple arrays, rearrange elements within it, or performing set operations upon it.

We use a consistent naming scheme that helps you quickly identify the functions you need. All functions except from*() take array as 1st parameter. Some functions operate on a specified range in the array and are called ranged*(), such as rangedPartialSort(). Functions like swap() are pure and do not modify the array itself, while functions like swap$() do modify (update) the array itself. Some functions accept a map function for faster comparison, such as unique(). Further, functions which return an iterable instead of an array are prefixed with i, such as isubsequences(). We borrow some names from other programming languages such as Haskell, Python, Java, and Processing.

With this package, you can simplify the implementation of complex algorithms, and be able to achieve your goals faster, regardless of your level of expertise. Try it out today and discover how it can transform your development experience! This package is available in Node.js and Web formats. To use it on the web, simply use the extra_array global variable after loading with a <script> tag from the jsDelivr CDN.

Stability: Experimental.

NOTE: The use of negative indices in certain functions such as slice() is provided as a convenience for access elements from the end of the array. However, negative indices can be thought of as referring to a virtual mirrored version of the original array, which can be counter-intuitive and make it harder to reason about the behavior of functions that use them. We are working on a solution to this problem. Any suggestions are welcome.

const xarray = require('extra-array');
// import * as xarray from "extra-array";
// import * as xarray from "https://unpkg.com/extra-array/index.mjs"; (deno)

var x = [1, 2, 3];
xarray.get(x, -1);
// → 3

var x = [1, 2, 3, 4];
xarray.swap(x, 0, 1);
// → [ 2, 1, 3, 4 ]

var x = [1, 2, 3, 4];
xarray.rotate(x, 1);
// → [ 2, 3, 4, 1 ]

xarray.permutations([1, 2, 3]);
// → [
//   [],          [ 1 ],
//   [ 2 ],       [ 3 ],
//   [ 1, 2 ],    [ 1, 3 ],
//   [ 2, 1 ],    [ 2, 3 ],
//   [ 3, 1 ],    [ 3, 2 ],
//   [ 1, 2, 3 ], [ 1, 3, 2 ],
//   [ 2, 1, 3 ], [ 2, 3, 1 ],
//   [ 3, 1, 2 ], [ 3, 2, 1 ]
// ]


Property Description
fromRange Generate array from given number range.
fromInvocation Generate array from repeated function invocation.
fromApplication Generate array from repeated function application.
fromIterable Convert an iterable to array.
fromIterable$ Convert an iterable to array!
shallowClone Shallow clone an array.
deepClone Deep clone an array.
is Check if value is an array.
keys Obtain all indices.
values Get all values.
entries Obtain all index-value pairs.
index Get zero-based index for an element in array.
indexRange Get zero-based index range for part of array.
isEmpty Check if an array is empty.
length Find the length of an array.
resize$ Resize an array to given length!
clear$ Remove all elements from an array!
get Get value at index.
getAll Get values at indices.
getPath Get value at path in a nested array.
hasPath Check if nested array has a path.
set Set value at index.
set$ Set value at index!
setPath$ Set value at path in a nested array!
swap Exchange two values.
swap$ Exchange two values!
swapRanges Exchange two ranges of values.
swapRanges$ Exchange two ranges of values!
remove Remove value at index.
remove$ Remove value at index!
removePath$ Remove value at path in a nested array!
isSorted Examine if array is sorted.
hasUnsortedValue Examine if array has an unsorted value.
searchUnsortedValue Find first index of an unsorted value.
sort Arrange values in order.
sort$ Arrange values in order!
partialSort Partially arrange values in order.
partialSort$ Partially arrange values in order!
minimum Find first smallest value.
minimumEntry Find first smallest entry.
maximum Find first largest value.
maximumEntry Find first largest entry.
range Find smallest and largest values.
rangeEntries Find smallest and largest entries.
minimums Find smallest values.
minimumEntries Find smallest entries.
maximums Find largest values.
maximumEntries Find largest entries.
searchMinimumValue Find first index of minimum value.
searchMaximumValue Find first index of maximum value.
searchMinimumValues Find indices of minimum values.
searchMaximumValues Find indices of maximum values.
isEqual Examine if two arrays are equal.
compare Compare two arrays (lexicographically).
head Get first value.
tail Get values except first.
init Get values except last.
last Get last value.
middle Get values from middle.
slice Get part of an array.
slice$ Get part of an array!
includes Check if array has a value.
hasValue Examine if array has a value.
searchValue Find first index of a value.
searchValueRight Find last index of a value.
searchValueAll Find indices of value.
searchAdjacentDuplicateValue Find first index of an adjacent duplicate value.
searchMismatchedValue Find first index where two arrays differ.
hasPrefix Examine if array starts with a prefix.
hasSuffix Examine if array ends with a suffix.
hasInfix Examine if array contains an infix.
hasSubsequence Examine if array has a subsequence.
hasPermutation Examine if array has a permutation.
prefixes Obtain all possible prefixes.
suffixes Obtain all possible suffixes.
infixes Obtain all possible infixes.
subsequences Obtain all possible subsequences.
permutations Obtain all possible permutations.
searchInfix Find first index of an infix.
searchInfixRight Find last index of an infix.
searchInfixAll Find indices of an infix.
searchSubsequence Find first index of a subsequence.
randomValue Pick an arbitrary value.
randomPrefix Pick an arbitrary prefix.
randomSuffix Pick an arbitrary suffix.
randomInfix Pick an arbitrary infix.
randomSubsequence Pick an arbitrary subsequence.
randomPermutation Pick an arbitrary permutation.
randomPermutation$ Pick an arbitrary permutation!
find Find first value passing a test.
findRight Find last value passing a test.
take Keep first n values only.
takeRight Keep last n values only.
takeWhile Keep values from left, while a test passes.
takeWhileRight Keep values from right, while a test passes.
drop Discard first n values only.
dropRight Discard last n values only.
dropWhile Discard values from left, while a test passes.
dropWhileRight Discard values from right, while a test passes.
scanWhile Scan from left, while a test passes.
scanWhileRight Scan from right, while a test passes.
scanUntil Scan from left, until a test passes.
scanUntilRight Scan from right, until a test passes.
indexOf Find first index of a value.
lastIndexOf Find last index of a value.
search Find index of first value passing a test.
searchRight Find index of last value passing a test.
searchAll Find indices of values passing a test.
forEach Call a function for each value.
some Examine if any value satisfies a test.
every Examine if all values satisfy a test.
map Transform values of an array.
map$ Transform values of an array!
reduce Reduce values of array to a single value.
reduceRight Reduce values from right, to a single value.
filter Keep values which pass a test.
filter$ Keep values which pass a test!
filterAt Keep values at given indices.
reject Discard values which pass a test.
reject$ Discard values which pass a test!
rejectAt Discard values at given indices.
flat Flatten nested array to given depth.
flatMap Flatten nested array, based on map function.
exclusiveScan Perform exclusive prefix scan from left to right.
exclusiveScan$ Perform exclusive prefix scan from left to right!
inclusiveScan Perform inclusive prefix scan from left to right.
inclusiveScan$ Perform inclusive prefix scan from left to right!
adjacentCombine Combine adjacent values of an array.
adjacentCombine$ Combine adjacent values of an array!
intersperse Place a separator between every value.
interpolate Estimate new values between existing ones.
intermix Place values of an array between another.
interleave Place values from iterables alternately.
zip Combine values from arrays.
fill Fill with given value.
fill$ Fill with given value!
push Add value to the end.
push$ Add values to the end!
pop Remove last value.
pop$ Remove last value!
shift Remove first value.
shift$ Remove first value!
unshift Add values to the start.
unshift$ Add values to the start!
copy Copy part of array to another.
copy$ Copy part of array to another!
copyWithin Copy part of array within.
copyWithin$ Copy part of array within!
moveWithin Move part of array within.
moveWithin$ Move part of array within!
splice Remove or replace existing values.
splice$ Remove or replace existing values!
count Count values which satisfy a test.
countEach Count occurrences of each distinct value.
partition Segregate values by test result.
partitionEach Segregate each distinct value.
split Break array considering test as separator.
splitAt Break array considering indices as separator.
cut Break array when test passes.
cutRight Break array after test passes.
cutAt Break array at given indices.
cutAtRight Break array after given indices.
group Keep similar values together and in order.
chunk Break array into chunks of given size.
concat Append values from arrays.
concat$ Append values from arrays!
join Join values together into a string.
cycle Obtain values that cycle through array.
repeat Repeat an array given times.
reverse Reverse the values.
reverse$ Reverse the values!
rotate Rotate values in array.
rotate$ Rotate values in array!
isUnique Examine if there are no duplicate values.
isDisjoint Examine if arrays have no value in common.
unique Remove duplicate values.
union Obtain values present in any array.
union$ Obtain values present in any array!
intersection Obtain values present in both arrays.
difference Obtain values not present in another array.
symmetricDifference Obtain values not present in both arrays.
cartesianProduct Obtain cartesian product of arrays.


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