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 ]
// ]

Index

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.

References

• Prefix sum array and difference array : Woburn C.I. PEGWiki
• How to get the count of each distinct value in a column?
• How to add region in java script file, visual studio
• Operator precedence - JavaScript : MDN Web Docs
• numpy.partition - NumPy Manual