Hash from two arrays

Task

Using two Arrays of equal length, create a Hash object where the elements from one array (the keys) are linked to the elements of the other (the values)

Related task

Associative arrays/Creation

AutoHotkey

<lang AutoHotkey>array1 := ["two", "three", "apple"] array2 := [2, 3, "fruit"] hash := {} Loop % array1.maxIndex()

  hash[array1[A_Index]] := array2[A_Index]

MsgBox % hash["apple"] "`n" hash["two"]</lang>

AWK

Awk arrays are used for both lists and hash maps. <lang awk># usage: awk -v list1="i ii iii" -v list2="1 2 3" -f hash2.awk BEGIN { if(!list1) list1="one two three" if(!list2) list2="1 2 3"

       split(list1, a);
       split(list2, b);
       for(i=1;i in a;i++) { c[a[i]] = b[i] };

       for(i in c) print i,c[i]

}</lang>

Output:

three 3
two 2
one 1

BASIC256

Solution is at Associative_array/Creation#BASIC256.

BBC BASIC

Works with: BBC BASIC for Windows

<lang bbcbasic> DIM array1$(4) : array1$() = "0", "1", "2", "3", "4"

     DIM array2$(4) : array2$() = "zero", "one", "two", "three", "four"
     
     FOR index% = 0 TO DIM(array1$(),1)
       PROCputdict(mydict$, array2$(index%), array1$(index%))
     NEXT
     PRINT FNgetdict(mydict$, "3")
     END
     
     DEF PROCputdict(RETURN dict$, value$, key$)
     IF dict$ = "" dict$ = CHR$(0)
     dict$ += key$ + CHR$(1) + value$ + CHR$(0)
     ENDPROC
     
     DEF FNgetdict(dict$, key$)
     LOCAL I%, J%
     I% = INSTR(dict$, CHR$(0) + key$ + CHR$(1))
     IF I% = 0 THEN = "" ELSE I% += LEN(key$) + 2
     J% = INSTR(dict$, CHR$(0), I%)
     = MID$(dict$, I%, J% - I%)</lang>

Bracmat

<lang bracmat> two three apple:?arr1 & 2 3 fruit:?arr2 & new$hash:?H & whl

 ' ( !arr1:%?k ?arr1
   & !arr2:%?v ?arr2
   & (H..insert)$(!k.!v)
   )

& (H..forall)$out & ; </lang>

Output:

apple.fruit
three.3
two.2

Brat

<lang brat>zip = { keys, values | h = [:] keys.each_with_index { key, index | h[key] = values[index] }

h }

p zip [1 2 3] [:a :b :c] #Prints [1: a, 2: b, 3: c]</lang>

There likely exist libraries that can be used for creating hashes that are better than the following implementation. There are also better functions for obtaining hash values from strings. The following implementation tries to be somewhat generic to facilitate using alternative key and value types. <lang c>#include <stdio.h>

include <stdlib.h>
include <string.h>

define KeyType const char *
define ValType int

define HASH_SIZE 4096

// hash function useful when KeyType is char * (string) unsigned strhashkey( const char * key, int max) {

   unsigned h=0;
   unsigned hl, hr;

   while(*key) {
       h += *key;
       hl= 0x5C5 ^ (h&0xfff00000 )>>18;
       hr =(h&0x000fffff );
       h = hl ^ hr ^ *key++;
   }
   return h % max;

}

typedef struct sHme {

   KeyType    key;
   ValType    value;
   struct sHme  *link;

} *MapEntry;

typedef struct he {

   MapEntry  first, last;

} HashElement;

HashElement hash[HASH_SIZE];

typedef void (*KeyCopyF)(KeyType *kdest, KeyType ksrc); typedef void (*ValCopyF)(ValType *vdest, ValType vsrc); typedef unsigned (*KeyHashF)( KeyType key, int upperBound ); typedef int (*KeyCmprF)(KeyType key1, KeyType key2);

void HashAddH( KeyType key, ValType value,

       KeyCopyF copyKey, ValCopyF copyVal, KeyHashF hashKey, KeyCmprF keySame )

{

   unsigned hix = (*hashKey)(key, HASH_SIZE);
   MapEntry m_ent;

   for (m_ent= hash[hix].first;
           m_ent && !(*keySame)(m_ent->key,key); m_ent=m_ent->link);
   if (m_ent) {
       (*copyVal)(&m_ent->value, value);
   }
   else {
       MapEntry last;
       MapEntry hme = malloc(sizeof(struct sHme));
       (*copyKey)(&hme->key, key);
       (*copyVal)(&hme->value, value);
       hme->link = NULL;
       last = hash[hix].last;
       if (last) {

// printf("Dup. hash key\n");

           last->link = hme;
       }
       else
           hash[hix].first = hme;
       hash[hix].last = hme;
   }

}

int HashGetH(ValType *val, KeyType key, KeyHashF hashKey, KeyCmprF keySame ) {

   unsigned hix = (*hashKey)(key, HASH_SIZE);
   MapEntry m_ent;
   for (m_ent= hash[hix].first;
           m_ent && !(*keySame)(m_ent->key,key); m_ent=m_ent->link);
   if (m_ent) {
       *val = m_ent->value;
   }
   return (m_ent != NULL);

}

void copyStr(const char**dest, const char *src) {

   *dest = strdup(src);

} void copyInt( int *dest, int src) {

   *dest = src;

} int strCompare( const char *key1, const char *key2) {

   return strcmp(key1, key2) == 0;

}

void HashAdd( KeyType key, ValType value ) {

   HashAddH( key, value, &copyStr, &copyInt, &strhashkey, &strCompare);

}

int HashGet(ValType *val, KeyType key) {

   return HashGetH( val, key, &strhashkey, &strCompare);

}

int main() {

   static const char * keyList[] = {"red","orange","yellow","green", "blue", "violet" };
   static int valuList[] = {1,43,640, 747, 42, 42};
   int ix;

   for (ix=0; ix<6; ix++) {
       HashAdd(keyList[ix], valuList[ix]);
   }
   return 0;

}</lang>

C++

Technically a std::map is a binary search tree, not a hash table, but it provides the same functionality. The C++11 standard incorporates hash tables. To use a hash table in C++11, simply change std::map to std::unordered_map. The core idea, turning two sequences into an associative mapping, is valid either way.

<lang cpp>#include <map>

include <string>

int main( int argc, char* argv[] ) {

std::string keys[] = { "1", "2", "3" } ;
std::string vals[] = { "a", "b", "c" } ;

std::map< std::string, std::string > hash ;

for( int i = 0 ; i < 3 ; i++ )
{
 hash[ keys[i] ] = vals[i] ;
}

}</lang>

Alternatively: <lang cpp>#include <map> // for std::map

include <algorithm> // for std::transform
include <string> // for std::string
include <utility> // for std::make_pair

int main() {

 std::string keys[] = { "one", "two", "three" };
 std::string vals[] = { "foo", "bar", "baz" };

 std::map<std::string, std::string> hash;

 std::transform(keys, keys+3,
                vals,
                std::inserter(hash, hash.end()),
                std::make_pair<std::string, std::string>);

}</lang>

C#

<lang csharp>System.Collections.HashTable h = new System.Collections.HashTable();

string[] arg_keys = {"foo","bar","val"}; string[] arg_values = {"little", "miss", "muffet"};

//Some basic error checking int arg_length = 0; if ( arg_keys.Length == arg_values.Length ) {

 arg_length = arg_keys.Length;

}

for( int i = 0; i < arg_length; i++ ){

 h.add( arg_keys[i], arg_values[i] );

}</lang>

Alternate way of adding values

<lang csharp>for( int i = 0; i < arg_length; i++ ){

 h[ arg_keys[i] ] = arg_values[i];

}</lang>

Ceylon

<lang ceylon>shared void run() { value keys = [1, 2, 3]; value items = ['a', 'b', 'c']; value hash = map(zipEntries(keys, items)); }</lang>

Clojure

<lang lisp>(zipmap [\a \b \c] [1 2 3])</lang>

Coco

<lang coco>keys = <[apple banana orange grape]> values = <[red yellow orange purple]>

object = new

   @[keys[i]] = values[i] for i til keys.length</lang>

CoffeeScript

 keys = ['a','b','c']
 values = [1,2,3]
 map = {}
 map[key] = values[i] for key, i in keys

</lang>

ColdFusion

<lang ColdFusion><cfscript> function makeHash(keyArray, valueArray) {

 var x = 1;
 var result = {};
 for( ; x <= ArrayLen(keyArray); x ++ ) {
   result[keyArray[x]] = valueArray[x];
 }
 return result;

}

keyArray = ['a', 'b', 'c']; valueArray = [1, 2, 3]; map = makeHash(keyArray, valueArray); </cfscript></lang>

Common Lisp

<lang lisp>(defun rosetta-code-hash-from-two-arrays (vector-1 vector-2 &key (test 'eql))

 (assert (= (length vector-1) (length vector-2)))
 (let ((table (make-hash-table :test test :size (length vector-1))))
   (map nil (lambda (k v) (setf (gethash k table) v))
            vector-1 vector-2)
   table))</lang>

Or, using cl:loop:

<lang lisp>(defun rosetta-code-hash-from-two-arrays (vector-1 vector-2 &key (test 'eql))

 (loop initially (assert (= (length vector-1) (length vector-2)))
       with table = (make-hash-table :test test :size (length vector-1))
       for k across vector-1
       for v across vector-2
       do (setf (gethash k table) v)
       finally (return table)))</lang>

In Common Lisp terminology, a vector is a one-dimensional array.

D

<lang d>void main() {

   import std.array, std.range;

   immutable hash = ["a", "b", "c"].zip([1, 2, 3]).assocArray;

}</lang>

Déjà Vu

<lang dejavu>local :h_keys [ :one :two :three ] local :h_values [ 1 2 3 ] local :h {} for item in h_keys:

   set-to h item pop-from h_values

</lang>

E

<lang e>def keys := ["one", "two", "three"] def values := [1, 2, 3] __makeMap.fromColumns(keys, values)</lang>

EchoLisp

<lang scheme> (lib 'hash)

(define H (make-hash)) (define keys '(elvis simon antoinette)) (define kvalues '("the king" "gallubert" "de gabolde d'Audan"))

(list->hash (map cons keys kvalues) H)

   → #hash:3

(hash-ref H 'elvis)

   → "the king"

</lang>

Elixir

<lang elixir>iex(1)> keys = [:one, :two, :three] [:one, :two, :three] iex(2)> values = [1, 2, 3] [1, 2, 3] iex(3)> Enum.zip(keys, values) |> Enum.into(Map.new) %{one: 1, three: 3, two: 2}</lang>

Erlang

<lang Erlang> Dictionary = dict:from_list( lists:zip([key1, key2, key3], [value1, 2, 3]) ). </lang>

F#

<lang fsharp>HashMultiMap(Array.zip [|"foo"; "bar"; "baz"|] [|16384; 32768; 65536|], HashIdentity.Structural)</lang>

Factor

<lang factor>USING: hashtables ; { "one" "two" "three" } { 1 2 3 } zip >hashtable</lang>

Falcon

<lang falcon> keys = [ 'a', 'b', 'c', 'd' ] values = [ 1, 2, 3, 4 ] hash = [ => ] for i in [ 0 : keys.len() ]: hash[ keys[ i ] ] = values[ i ] </lang>

Fantom

<lang fantom> class Main {

 public static Void main ()
 {
   keys := [1,2,3,4,5]
   values := ["one", "two", "three", "four", "five"]

   // create an empty map
   map := [:]  
   // add the key-value pairs to it
   keys.size.times |Int index|
   {
     map.add(keys[index], values[index])
   }
 }

} </lang>

Frink

There is a built-in dictionary/hash constructor that takes two arrays as input. <lang frink> a = new dict[["a", "b", "c"], [1, 2, 3]] </lang>

Go

<lang go>package main

import "fmt"

func main() {

   keys := []string{"a", "b", "c"}
   vals := []int{1, 2, 3}
   hash := map[string]int{}
   for i, key := range keys {
       hash[key] = vals[i]
   }
   fmt.Println(hash)

}</lang>

Output:

map[b:2 a:1 c:3]

Groovy

<lang groovy>def keys = ['a','b','c'] def vals = ['aaa', 'bbb', 'ccc'] def hash = [:] keys.eachWithIndex { key, i ->

hash[key] = vals[i]

}</lang>

Alternative Version: <lang groovy>List.metaClass.hash = { list -> [delegate, list].transpose().collectEntries { [(it[0]): it[1]] } }</lang>

Test: <lang groovy>assert (['a', 'b', 'c'].hash(['aaa', 'bbb', 'ccc'])) == [a: 'aaa', b: 'bbb', c: 'ccc']</lang>

Harbour

<lang visualfoxpro>LOCAL arr1 := { 6, "eight" }, arr2 := { 16, 8 } LOCAL hash := { => } LOCAL i, j

FOR EACH i, j IN arr1, arr2

  hash[ i ] := j

NEXT</lang>

Haskell

Works with: GHCi version 6.6

<lang haskell>import Data.Map

makeMap ks vs = fromList $ zip ks vs mymap = makeMap ['a','b','c'] [1,2,3]</lang>

Icon and Unicon

<lang Icon>link ximage # to format the structure

procedure main(arglist) #: demonstrate hash from 2 lists local keylist

if *arglist = 0 then arglist := [1,2,3,4] # ensure there's a list every put(keylist := [], "key-" || !arglist) # make keys for each entry

every (T := table())[keylist[ i := 1 to *keylist ]] := arglist[i] # create the hash table

write(ximage(T)) # show result end</lang>

Ioke

<lang ioke>{} addKeysAndValues([:a, :b, :c], [1, 2, 3])</lang>

J

What exactly is a hash?

We shall interpret 'hash' as "a function between some arbitrary values and some other arbitrary values". (Technically speaking a hash is more of a reference to a collection of techniques for achieving this, with something of an emphasis on an arbitrary and opaque intermediate result, than the actual end result. But people have spoken very glowingly of these techniques so let's pretend that the result actually matters.)

Solution: <lang j>hash=: vals {~ keys&i.</lang> For example:

<lang j> keys=: 10?.100

  vals=: > ;:'zero one two three four five six seven eight nine'
  hash=: vals {~ keys&i.

  keys

46 99 23 62 42 44 12 5 68 63

  $vals

10 5

  hash 46

zero

  hash 99

one

  hash 63 5 12 5 23

nine seven six seven two</lang> Here, keys is a list of 10 integers between 0 and 99 chosen arbitrarily (we like to call this "randomly" but there is some mathematical controversy about implementations of randomness) without repetition, and vals is a 10 by 5 character matrix.

Java

<lang java>import java.util.HashMap; public static void main(String[] args){ String[] keys= {"a", "b", "c"}; int[] vals= {1, 2, 3}; HashMap<String, Integer> hash= new HashMap<String, Integer>();

for(int i= 0; i < keys.length; i++){ hash.put(keys[i], vals[i]); } }</lang>

JavaScript

Iterative

<lang javascript> var keys = ['a', 'b', 'c']; var values = [1, 2, 3]; var map = {}; for(var i = 0; i < keys.length; i += 1) {

 map[ keys[i] ] = values[i];

} </lang>

Iterative Using Foreach

<lang javascript> function arrToObj(keys, vals) {

 var map = {};
 keys.forEach(function (key, index) {
   map[key] = val[index];
 });
 return map;

} </lang>

Using Reduce

<lang javascript> function arrToObj(keys, vals) {

 return keys.reduce(function(map, key, index) {
   map[key] = vals[index];
   return map;
 }, {});

} </lang>

jq

jq only supports hashing of strings. In the following, accordingly, we assume that one array (keys) is an array of strings. <lang jq># hash(keys) creates a JSON object with the given keys as keys

and values taken from the input array in turn.
"keys" must be an array of strings.
The input array may be of any length and have values of any type,
but only the first (keys|length) values will be used;
the input will in effect be padded with nulls if required.

def hash(keys):

 . as $values
 | reduce range(0; keys|length) as $i
     ( {}; . + { (keys[$i]) : $values[$i] });

[1,2,3] | hash( ["a","b","c"] )</lang>

Output:

<lang jq>jq -n -f Hash_from_two_arrays.jq {

 "a": 1,
 "b": 2,
 "c": 3

}</lang> To hash an array of distinct integers, the tostring filter can be used, e.g.

[10,20,30] | hash( [1,2,3] | map(tostring) )

yields:<lang jq>{

 "1": 10,
 "2": 20,
 "3": 30

}</lang>

Julia

Translation of: Python

Using a dictionary comprehension: <lang julia>julia> K = ["a", "b", "c"] julia> V = [1, 2, 3] julia> H = [key => value for (key, value) in zip(K,V)] {"b"=>2,"c"=>3,"a"=>1}</lang> The comprehension can also be typed, in order to restrict the dictionary to certain key/value types: <lang julia>julia> H = (String=>Int)[key => value for (key, value) in zip(K,V)] ["b"=>2,"c"=>3,"a"=>1]</lang> Using a dictionary constructor function (Dict): <lang julia>julia> H = Dict(K, V) ["b"=>2,"c"=>3,"a"=>1]</lang>

K

The keys in a dictionary must be a symbol. <lang K> a: `zero `one `two / symbols

  b: 0 1 2

  d:. a,'b  / create the dictionary

.((`zero;0;)

 (`one;1;)
 (`two;2;))

  d[`one]

1</lang>

Here we use integers as keys (which must be converted to symbols) and strings as values (here also converted to symbols).

<lang K> keys: !10 / 0..9

  split:{1_'(&x=y)_ x:y,x}
  vals:split["zero one two three four five six seven eight nine";" "]

  s:{`$$x}  / convert to symbol
  d:. (s'keys),'s'vals

.((`"0";`zero;)

 (`"1";`one;)
 (`"2";`two;)
 (`"3";`three;)
 (`"4";`four;)
 (`"5";`five;)
 (`"6";`six;)
 (`"7";`seven;)
 (`"8";`eight;)
 (`"9";`nine;))

  $d[s 1] / leading "$" converts back to string

"one"</lang>

Lasso

<lang Lasso>local( array1 = array('a', 'b', 'c'), array2 = array(1, 2, 3), hash = map )

loop(#array1 -> size) => { #hash -> insert(#array1 -> get(loop_count) = #array2 -> get(loop_count)) }

hash</lang>

-> map(a = 1, b = 2, c = 3)

Lang5

<lang lang5>: >table 2 compress -1 transpose ; ['one 'two 'three 'four] [1 2 3 4] >table</lang>

LFE

<lang lisp>(let* ((keys (list 'foo 'bar 'baz))

      (vals (list '"foo data" '"bar data" '"baz data"))
      (tuples (: lists zipwith
                (lambda (a b) (tuple a b)) keys vals))
      (my-dict (: dict from_list tuples)))
 (: io format '"fetched data: ~p~n" (list (: dict fetch 'baz my-dict))))

</lang>

Lingo

<lang lingo>keys = ["a","b","c"] values = [1,2,3]

props = [:] cnt = keys.count repeat with i = 1 to cnt

 props[keys[i]] = values[i]

end repeat

put props -- ["a": 1, "b": 2, "c": 3]</lang>

LiveCode

<lang LiveCode>put "a,b,c" into list1 put 10,20,30 into list2 split list1 using comma split list2 using comma repeat with i=1 to the number of elements of list1

   put list2[i] into list3[list1[i]]

end repeat combine list3 using comma and colon put list3

-- ouput -- a:10,b:20,c:30</lang>

Lua

<lang lua>function(keys,values)

 local t = {}
 for i=1, #keys do
   t[keys[i]] = values[i]
 end

end</lang>

Maple

<lang Maple>A := [1, 2, 3]; B := ["one", "two", three"]; T := table( zip( `=`, A, B ) );</lang>

Mathematica

<lang Mathematica>Map[(Hash[Part[#, 1]] = Part[#, 2]) &,

Transpose[{{1, 2, 3}, {"one", "two", "three"}}]]

?? Hash ->Hash[1]=one ->Hash[2]=two ->Hash[3]=three</lang>

MATLAB / Octave

See Associative arrays/Creation for clarification of limitations and differences between the two methods.

MATLAB/Octave: structs

<lang MATLAB>function s = StructFromArrays(allKeys, allVals) % allKeys must be cell array of strings of valid field-names % allVals can be cell array or array of numbers % Assumes arrays are same size and valid types

   s = struct;
   if iscell(allVals)
       for k = 1:length(allKeys)
           s.(allKeys{k}) = allVals{k};
       end
   else
       for k = 1:length(allKeys)
           s.(allKeys{k}) = allVals(k);
       end
   end

end</lang>

Output:

>> ages = StructFromArrays({'Joe' 'Bob' 'Sue'}, [21 35 27])

ages = 

    Joe: 21
    Bob: 35
    Sue: 27

MATLAB only: containers.Map

containers.Map constructor provides this functionality already.

>> ages = containers.Map({'Joe' 'Bob' 'Sue'}, [21 35 27]);
>> keys(ages)

ans = 

    'Bob'    'Joe'    'Sue'

>> values(ages)

ans = 

    [35]    [21]    [27]

NetRexx

REXX Style

Translation of: REXX

<lang netrexx>/* NetRexx program ****************************************************

04.11.2012 Walter Pachl derived from REXX
- - - - /

options replace format comments java crossref savelog symbols nobinary

 values='triangle quadrilateral pentagon hexagon heptagon octagon' -
        'nonagon decagon dodecagon'
 keys  ='three four five six seven eight nine ten twelve'
 kcopy=keys
 k=                                 /* initialize the arrays      */
 v=
 value='unknown'
 Loop i=1 By 1 While kcopy>         /* initialize the two arrays  */
   Parse kcopy  ki kcopy;  k[i]=ki
   Parse values vi values; v[i]=vi
   End
 Loop j=1 To i-1
   value[k[j]]=v[j]
   End
 Say 'Enter one of these words:'
 Say ' 'keys
 Parse Ask z
 Say z '->' value[z]</lang>

Java Collections

NetRexx has access to Java's Collection objects too. <lang NetRexx>/* NetRexx */ options replace format comments java crossref symbols nobinary

vals = [ 'zero', 'one', 'two', 'three', 'four', 'five' ] keys = [ 'k0', 'k1', 'k2', 'k3', 'k4', 'k5' ] hash1 = Rexx hash2 = Map

hash1 = HashMap() hash2 = makeHash(hash1, keys, vals) -- using a Map object (overloaded method) makeHash(hash2, keys, vals) -- using a Rexx object (overloaded method)

return

-- Using a Java collection object method makeHash(hash = Map, keys = Rexx[], vals = Rexx[]) static

 loop k_ = 0 to keys.length - 1
   hash.put(keys[k_], vals[k_])
   end k_

 key = Rexx
 loop key over hash.keySet()
   say key.right(8)':' hash.get(key)
   end key
 say

 return

-- For good measure a version using the default Rexx object as a hash (associative array) method makeHash(hash = Rexx, keys = Rexx[], vals = Rexx[]) static

 loop k_ = 0 to keys.length - 1
   hash[keys[k_]] = vals[k_]
   end k_

 loop key over hash
   say key.right(8)':' hash[key]
   end key
 say

 return

</lang>

Nemerle

<lang Nemerle>using System; using System.Console; using Nemerle.Collections; using Nemerle.Collections.NCollectionsExtensions;

module AssocArray {

   Main() : void
   {
       def list1 = ["apples", "oranges", "bananas", "kumquats"];
       def list2 = [13, 34, 12];
       def inventory = Hashtable(ZipLazy(list1, list2));
       foreach (item in inventory)
           WriteLine("{0}:   {1}", item.Key, item.Value);
   }

}</lang>

Nim

<lang nim>import tables, sequtils

let keys = @['a','b','c'] let values = @[1, 2, 3]

let table = toTable zip(keys, values)</lang>

Objeck

<lang objeck> use Structure;

bundle Default {

 class HashOfTwo {
   function : Main(args : System.String[]) ~ Nil {
     keys := ["1", "2", "3"];
     vals := ["a", "b", "c"];
     hash := StringHash->New();
     each(i : vals) {
       hash->Insert(keys[i], vals[i]->As(Base));
     };
   }
 }

} </lang>

Objective-C

<lang objc>NSArray *keys = @[@"a", @"b", @"c"]; NSArray *values = @[@1, @2, @3]; NSDictionary *dict = [NSDictionary dictionaryWithObjects:values forKeys:keys];</lang>

Oberon-2

Works with oo2c version 2 <lang oberon2> MODULE HashFromArrays; IMPORT

 ADT:Dictionary,
 Object:Boxed;

TYPE

 Key= STRING;
 Value= Boxed.LongInt;
 
 PROCEDURE Do;
 VAR
   a: ARRAY 128 OF Key;
   b: ARRAY 128 OF Value;
   hash: Dictionary.Dictionary(Key,Value);
   i: INTEGER;
   
 BEGIN
   hash := NEW(Dictionary.Dictionary(Key,Value));
   a[0] := "uno";
   a[1] := "dos";
   a[2] := "tres";
   a[3] := "cuatro";
   b[0] := Boxed.ParseLongInt("1");
   b[1] := Boxed.ParseLongInt("2");
   b[2] := Boxed.ParseLongInt("3");
   b[3] := Boxed.ParseLongInt("4");
   i := 0;
   WHILE (i < LEN(a)) & (a[i] # NIL) DO
     hash.Set(a[i],b[i]);
     INC(i)
   END;
   
 END Do;

BEGIN

Do;

END HashFromArrays. </lang>

OCaml

The idiomatic solution uses lists rather than arrays.

<lang ocaml>let keys = [ "foo"; "bar"; "baz" ] and vals = [ 16384; 32768; 65536 ] and hash = Hashtbl.create 0;;

List.iter2 (Hashtbl.add hash) keys vals;;</lang>

In the extremely unlikely event that it was actually necessary to use arrays, the solution would become slightly less elegant: (except using the ExtLib which provides the equivalent Array.iter2)

<lang ocaml>let keys = [| "foo"; "bar"; "baz" |] and vals = [| 16384; 32768; 65536 |] and hash = Hashtbl.create 0;;

for i = 0 to Array.length keys - 1 do

 Hashtbl.add hash keys.(i) vals.(i)

done;;</lang>

In either case, an exception is raised if the inputs are different lengths.

If you want to use functional binary search trees instead of hash tables:

<lang ocaml>module StringMap = Map.Make (String);;

let keys = [ "foo"; "bar"; "baz" ] and vals = [ 16384; 32768; 65536 ] and map = StringMap.empty;;

let map = List.fold_right2 StringMap.add keys vals map;;</lang>

ooRexx

<lang ooRexx>array1 = .array~of("Rick", "Mike", "David") array2 = .array~of("555-9862", "555-5309", "555-6666")

-- if the index items are constrained to string objects, this can -- be a directory too. hash = .table~new

loop i = 1 to array1~size

   hash[array1[i]] = array2[i]

end Say 'Enter a name' Parse Pull name Say name '->' hash[name]</lang>

Output:

Enter a name
Rick
Rick -> 555-9862

Oz

<lang oz>declare

 fun {ZipRecord Keys Values}
    {List.toRecord unit {List.zip Keys Values MakePair}}
 end

 fun {MakePair A B}
    A#B
 end

in

 {Show {ZipRecord [a b c] [1 2 3]}}</lang>

PARI/GP

<lang parigp>hash(key, value)=Map(matrix(#key,2,x,y,if(y==1,key[x],value[x])));</lang>

Pascal

Works with: Free_Pascal

Library: contnrs

<lang pascal>program HashFromTwoArrays (Output);

uses

 contnrs;

var

 keys:   array[1..3] of string  = ('a', 'b', 'c');
 values: array[1..3] of integer = ( 1,   2,   3 );
 hash:   TFPDataHashTable;
 i:      integer;

begin

 hash := TFPDataHashTable.Create;
 for i := low(keys) to high(keys) do
   hash.add(keys[i], @values[i]);
 writeln ('Length of hash table: ', hash.Count);
 hash.Destroy;

end.</lang>

Output:

% ./HashFromTwoArrays
Length of hash table: 3

Perl

Alternatively, using

Library: List::MoreUtils MoreUtils

:

<lang perl>use List::MoreUtils qw(zip); my %hash = zip @keys, @vals;</lang>

Perl 6

Using the "zipwith" meta-operator on the => pair composer:

Works with: rakudo version 2015-09-13

<lang perl6>my @keys = <a b c d e>; my @values = ^5;

my %hash = @keys Z=> @values;</lang>

Alternatively, by assigning to a hash slice:

<lang perl6>my %hash; %hash{@keys} = @values;</lang>

Or to create an anonymous hash:

<lang perl6>%( @keys Z=> @values )</lang> All of these zip forms trim the result to the length of the shorter of their two input lists. If you wish to enforce equal lengths, you can use a strict hyperoperator instead: <lang perl6>{ @keys »=>« @values } # Will fail if the lists differ in length</lang>

Phix

<lang Phix>function make_hash(sequence keyarray, sequence valuearray) integer dict = new_dict()

   for i=1 to length(keyarray) do
       setd(keyarray[i],valuearray[i],dict)
   end for
   return dict

end function

integer dict = make_hash({1,"two",PI},{"one",2,PI}) ?getd(1,dict) ?getd("two",dict) ?getd(PI,dict)</lang>

Output:

"one"
2
3.141592654

PHP

Works with: PHP version 5

<lang php>$keys = array('a', 'b', 'c'); $values = array(1, 2, 3); $hash = array_combine($keys, $values);</lang>

Works with: PHP version 4

<lang php>$keys = array('a', 'b', 'c'); $values = array(1, 2, 3); $hash = array(); for ($idx = 0; $idx < count($keys); $idx++) {

 $hash[$keys[$idx]] = $values[$idx];

}</lang>

PicoLisp

<lang PicoLisp>(let (Keys '(one two three) Values (1 2 3))

  (mapc println
     (mapcar cons Keys Values) ) )</lang>

Output:

(one . 1)
(two . 2)
(three . 3)

Pop11

<lang pop11>vars keys = { 1 a b c}; vars vals = { 2 3 valb valc}; vars i;

Create hash table

vars ht = newmapping([], 500, 0, true);

Loop over input arrays (vectors)

for i from 1 to length(keys) do

 vals(i) -> ht(keys(i));

endfor;</lang>

PostScript

Library: initlib

<lang postscript> % push our arrays

[/a /b /c /d /e] [1 2 3 4 5]

% create a dict with it {aload pop} dip let currentdict end % show that we have created the hash

{= =} forall

</lang>

PowerShell

<lang powershell>function create_hash ([array] $keys, [array] $values) {

   $h = @{}
   if ($keys.Length -ne $values.Length) {
       Write-Error -Message "Array lengths do not match" `
                   -Category InvalidData `
                   -TargetObject $values
   } else {
       for ($i = 0; $i -lt $keys.Length; $i++) {
           $h[$keys[$i]] = $values[$i]
       }
   }
   return $h

}</lang>

Prolog

<lang prolog>% this one with side effect hash table creation

-dynamic hash/2.

make_hash([],[]). make_hash([H|Q],[H1|Q1]):- assert(hash(H,H1)), make_hash(Q,Q1).

-make_hash([un,deux,trois],[[a,b,c],[d,e,f],[g,h,i]])

% this one without side effects

make_hash_pure([],[],[]). make_hash_pure([H|Q],[H1|Q1],[hash(H,H1)|R]):- make_hash_pure(Q,Q1,R).

-make_hash_pure([un,deux,trois],[[a,b,c],[d,e,f],[g,h,i]],L),findall(M,(member(M,L),assert(M)),L).</lang>

PureBasic

<lang PureBasic>Dim keys.s(3) Dim vals.s(3) NewMap Hash.s()

keys(0)="a" : keys(1)="b" : keys(2)="c" : keys(3)="d" vals(0)="1" : vals(1)="2" : vals(2)="3" : vals(3)="4" For n = 0 To 3

   Hash(keys(n))= vals(n)

Next ForEach Hash()

  Debug Hash()

Next</lang>

Python

Works with: Python version 3.0+ and 2.7

Shows off the dict comprehensions in Python 3 (that were back-ported to 2.7): <lang python>keys = ['a', 'b', 'c'] values = [1, 2, 3] hash = {key: value for key, value in zip(keys, values)}</lang>

Works with: Python version 2.2+

<lang python>keys = ['a', 'b', 'c'] values = [1, 2, 3] hash = dict(zip(keys, values))

Lazily, Python 2.3+, not 3.x:

from itertools import izip hash = dict(izip(keys, values))</lang>

Works with: Python version 2.0+

<lang python>keys = ['a', 'b', 'c'] values = [1, 2, 3] hash = {} for k,v in zip(keys, values):

   hash[k] = v</lang>

The original (Ruby) example uses a range of different types as keys. Here is similar in python (run at the shell): <lang python>>>> class Hashable(object): def __hash__(self): return id(self) ^ 0xBEEF

>>> my_inst = Hashable() >>> my_int = 1 >>> my_complex = 0 + 1j >>> my_float = 1.2 >>> my_string = "Spam" >>> my_bool = True >>> my_unicode = u'Ham' >>> my_list = ['a', 7] >>> my_tuple = ( 0.0, 1.4 ) >>> my_set = set(my_list) >>> def my_func(): pass

>>> class my_class(object): pass

>>> keys = [my_inst, my_tuple, my_int, my_complex, my_float, my_string, my_bool, my_unicode, frozenset(my_set), tuple(my_list), my_func, my_class] >>> values = range(12) >>> d = dict(zip(keys, values)) >>> for key, value in d.items(): print key, ":", value

1 : 6 1j : 3 Ham : 7 Spam : 5 (0.0, 1.3999999999999999) : 1 frozenset(['a', 7]) : 8 1.2 : 4 ('a', 7) : 9 <function my_func at 0x0128E7B0> : 10 <class '__main__.my_class'> : 11 <__main__.Hashable object at 0x012AFC50> : 0 >>> # Notice that the key "True" disappeared, and its value got associated with the key "1" >>> # This is because 1 == True in Python, and dictionaries cannot have two equal keys</lang>

R

Assuming that the keys are coercible to character form, we can simply use the names attribute to create a hash. This example is taken from the Wikipedia page on hash tables. <lang r># Set up hash table keys <- c("John Smith", "Lisa Smith", "Sam Doe", "Sandra Dee", "Ted Baker") values <- c(152, 1, 254, 152, 153) names(values) <- keys

Get value corresponding to a key

values["Sam Doe"] # vals["Sam Doe"]

Get all keys corresponding to a value

names(values)[values==152] # "John Smith" "Sandra Dee"</lang>

Racket

Alternatively: <lang racket> (define (connect keys vals) (for/hash ([k keys] [v vals]) (values k v)))

Example

(connect #("a" "b" "c" "d") #(1 2 3 4)) </lang>

Raven

<lang raven>[ 'a' 'b' 'c' ] as $keys [ 1 2 3 ] as $vals $keys $vals combine as $hash</lang>

REXX

<lang rexx>/*REXX program demonstrates hashing of a stemmed array (from a key). */

                                      /*names of the 9 regular polygons*/

values='triangle quadrilateral pentagon hexagon heptagon octagon nonagon decagon dodecagon' keys ='thuhree vour phive sicks zeaven ate nein den duzun'

                          /* [↑]  superfluous blanks added to humorous */
                          /*      keys just because it looks prettier. */

call hash values,keys /*hash the keys to the values. */ parse arg query . /*get what was specified on C.L. */ if query== then exit /*Nothing? Then leave Dodge City*/ pad=left(,30) /*used for padding the display. */ say 'key:' query pad "value:" hash.query /*show some stuff.*/ exit /*stick a fork in it, we're done.*/ /*──────────────────────────────────HASH subroutine─────────────────────*/ hash: procedure expose hash.; parse arg v,k,hash.

           do j=1  until map==;            map=word(k,j)
                                        hash.map=word(v,j)
           end   /*j*/

return</lang>

Output:

when using the input of

phive

key: phive                                value: pentagon

Ruby

<lang ruby> keys = ['hal',666,[1,2,3]] vals = ['ibm','devil',123]

hash = Hash[keys.zip(vals)]

p hash # => {"hal"=>"ibm", 666=>"devil", [1, 2, 3]=>123}

retrieve the value linked to the key [1,2,3]

puts hash[ [1,2,3] ] # => 123 </lang>

Or define a new method in class Array:

<lang ruby> class Array

 def zip_hash(other)
   Hash[self.zip(other)]
 end

end

hash = %w{ a b c }.zip_hash( %w{ 1 2 3 } ) p hash # => {"a"=>"1", "b"=>"2", "c"=>"3"} </lang>

Hash[] is calling "to_hash" inside. Therefore, it doesn't work out when making a method name "to_hash".

In Ruby 2.1 the method "to_h" was introduced: <lang ruby>keys = ['hal', 666, [1,2,3]] vals = ['ibm', 'devil', 123]

keys.zip(vals).to_h</lang>

Rust

<lang rust>use std::collections::HashMap;

fn main() {

   let keys = ["a", "b", "c"];
   let values = [1, 2, 3];

   let hash = keys.iter().zip(values.iter()).collect::<HashMap<_, _>>();
   println!("{:?}", hash);

}</lang>

Sather

<lang sather>class ZIPPER{K,E} is

 zip(k:ARRAY{K}, e:ARRAY{E}) :MAP{K, E} 
   pre k.size = e.size
 is
   m :MAP{K, E} := #;
   loop m[k.elt!] := e.elt!; end;
   return m;    
 end;

end;

class MAIN is

 main is
   keys:ARRAY{STR} := |"one", "three", "four"|;
   values:ARRAY{INT} := |1, 3, 4|;
   m ::= ZIPPER{STR,INT}::zip(keys, values);
   loop 
     #OUT + m.pair! + " "; 
   end;
   #OUT + "\n";
 end;

end;</lang>

Scala

<lang scala>val keys = List(1, 2, 3) val values = Array("A", "B", "C") // Array mixed with List val map = keys.zip(values).toMap // and other Seq are possible.

// Testing assert(map == Map(1 ->"A", 2 -> "B", 3 -> "C")) println("Successfully completed without errors.")</lang>

Scheme

Using SRFI 69: <lang scheme>(define (lists->hash-table keys values . rest)

 (apply alist->hash-table (map cons keys values) rest))</lang>

Seed7

<lang seed7>$ include "seed7_05.s7i";

const type: numericHash is hash [string] integer; var numericHash: myHash is numericHash.value;

const proc: main is func

 local
   var array string: keyList is [] ("one", "two", "three");
   var array integer: valueList is [] (1, 2, 3);
   var integer: number is 0;
 begin
   for number range 1 to length(keyList) do
     myHash @:= [keyList[number]] valueList[number];
   end for;
 end func;</lang>

Sidef

<lang ruby>var keys = %w(a b c) var vals = [1, 2, 3]

var hash = Hash() hash{keys...} = vals... say hash</lang>

Smalltalk

Works with: GNU Smalltalk

<lang smalltalk>Array extend [

 dictionaryWithValues: array [ |d|
   d := Dictionary new.
   1 to: ((self size) min: (array size)) do: [:i|
     d at: (self at: i) put: (array at: i).
   ].
   ^ d
 ]

].

({ 'red' . 'one' . 'two' }

dictionaryWithValues: { '#ff0000'. 1. 2 }) displayNl.</lang>

Works with: Smalltalk/X

Works with: VisualWorks Smalltalk

<lang smalltalk>Dictionary

   withKeys:#('one' 'two' 'three')
   andValues:#('eins' 'zwei' 'drei')</lang>

Works with: Smalltalk/X

<lang smalltalk>Dictionary withAssociations:{ 'one'->1 . 'two'->2 . 'three'->3 }</lang>

SNOBOL4

Works with: Macro Spitbol

Works with: Snobol4+

Works with: CSnobol

<lang SNOBOL4>* # Fill arrays

       keys = array(5); vals = array(5)
       ks = 'ABCDE'; vs = '12345'

kloop i = i + 1; ks len(1) . keys = :s(kloop) vloop j = j + 1; vs len(1) . vals<j> = :s(vloop)

# Create hash
hash = table(5)
hloop k = k + 1; hash<keys<k>> = vals<k> :s(hloop)
# Test and display
ts = 'ABCDE'
tloop ts len(1) . ch = :f(out)
str = str ch ':' hash<ch> ' ' :(tloop)
out output = str end</lang>

Output:
A:1 B:2 C:3 D:4 E:5
Sparkling
<lang sparkling>let keys = { "foo", "bar", "baz" }; let vals = { 13, 37, 42 }; var hash = {}; for var i = 0; i < sizeof keys; i++ {
hash[keys[i]] = vals[i];
}</lang>
Standard ML
Works with: SML/NJ
Using functional binary search trees instead of hash tables:
<lang sml>structure StringMap = BinaryMapFn (struct
type ord_key = string val compare = String.compare end);
val keys = [ "foo", "bar", "baz" ] and vals = [ 16384, 32768, 65536 ] and myMap = StringMap.empty;
val myMap = foldl StringMap.insert' myMap (ListPair.zipEq (keys, vals));</lang>
Works with: SML/NJ
Using hash tables:
<lang sml>exception NotFound;
val keys = [ "foo", "bar", "baz" ] and vals = [ 16384, 32768, 65536 ] and hash = HashTable.mkTable (HashString.hashString, op=) (42, NotFound);
ListPair.appEq (HashTable.insert hash) (keys, vals);</lang>
Swift
Works with: Swift version 1.2+
<lang swift>let keys = ["a","b","c"] let vals = [1,2,3] var hash = [String: Int]() for (key, val) in zip(keys, vals) {
hash[key] = val
}</lang>
Tcl
Arrays in Tcl are automatically associative, i.e. there are no "not hashed arrays".
If we can take "arrays of equal length" to mean "lists of equal length", then the task might look like this: <lang tcl>set keys [list fred bob joe] set values [list barber plumber tailor] array set arr {} foreach a $keys b $values { set arr($a) $b }
parray arr</lang>

Output:
arr(bob) = plumber arr(fred) = barber arr(joe) = tailor
Alternatively, a dictionary could be used: <lang tcl>package require Tcl 8.5
set keys [list fred bob joe] set values [list barber plumber tailor]
foreach a $keys b $values {
dict set jobs $a $b
}
puts "jobs: [dict get $jobs]"</lang>

Output:
jobs: fred barber bob plumber joe tailor
TXR
One-liner, using quasiquoted hash syntax
<lang bash>$ txr -p '^#H(() ,*[zip #(a b c) #(1 2 3)])))'
H(() (c 3) (b 2) (a 1))</lang>
One-liner, using hash-construct function
<lang bash>$ txr -p '(hash-construct nil [zip #(a b c) #(1 2 3)])))'
H(() (c 3) (b 2) (a 1))</lang>
Explicit construction and stuffing
<lang txrlisp>(defun hash-from-two (vec1 vec2 . hash-args)
(let ((table (hash . hash-args))) (mapcar (do sethash table) vec1 vec2) table))
(prinl (hash-from-two #(a b c) #(1 2 3)))</lang>
$ ./txr hash-from-two.tl #H(() (c 3) (b 2) (a 1))
UnixPipes
Using a sorted file as an associative array (see Creating an associative array for usage.)
<lang bash>cat <<VAL >p.values apple boy cow dog elephant VAL
cat <<KEYS >p.keys a b c d e KEYS
paste -d\ <(cat p.values | sort) <(cat p.keys | sort)</lang>
UNIX Shell
Works with: Bash version 4
<lang bash>keys=( foo bar baz ) values=( 123 456 789 ) declare -A hash
for (( i = 0; i < ${#keys[@]}; i++ )); do
hash["${keys[i]}"]=${values[i]}
done
for key in "${!hash[@]}"; do
printf "%s => %s\n" "$key" "${hash[$key]}"
done</lang>

Output:
bar => 456 baz => 789 foo => 123
Ursala
There is a built-in operator for this. <lang Ursala>keys = <'foo','bar','baz'> values = <12354,145430,76748>
hash_function = keys-$values</lang> test program: <lang Ursala>#cast %nL
test = hash_function* <'bar','baz','foo','bar'></lang>

Output:
<145430,76748,12354,145430>
Vala
Library: Gee
<lang vala> using Gee;
void main(){
// mostly copied from C# example var hashmap = new HashMap<string, string>();
string[] arg_keys = {"foo", "bar", "val"}; string[] arg_values = {"little", "miss", "muffet"};
if (arg_keys.length == arg_values.length ){
for (int i = 0; i < arg_keys.length; i++){
hashmap[arg_keys[i]] = arg_values[i];
}
}
} </lang>
VBScript
VBScript (and Visual Basic in general) calls hashes "dictionary objects".
<lang vb>Set dict = CreateObject("Scripting.Dictionary") os = Array("Windows", "Linux", "MacOS") owner = Array("Microsoft", "Linus Torvalds", "Apple") For n = 0 To 2
dict.Add os(n), owner(n)
Next MsgBox dict.Item("Linux") MsgBox dict.Item("MacOS") MsgBox dict.Item("Windows")</lang>

Output:

(in message boxes)

Linus Torvalds Apple Microsoft
Visual Basic
Translation of: VBScript
The VBScript version can be used in Visual Basic unchanged, although it requires a reference to the Microsoft Scripting Runtime (scrrun.dll).
Alternately, instead of a Dictionary object, you can also use a Collection object, which serves a similar purpose, without the inclusion of an additional runtime library. In fact, the only immediately-obvious difference between this and the VBScript example is dict's data type, and the order that the arguments are passed to the Add method.
<lang vb>Dim dict As New Collection os = Array("Windows", "Linux", "MacOS") owner = Array("Microsoft", "Linus Torvalds", "Apple") For n = 0 To 2
dict.Add owner(n), os(n)
Next Debug.Print dict.Item("Linux") Debug.Print dict.Item("MacOS") Debug.Print dict.Item("Windows")</lang>
Wortel
Wortel has an inbuilt operator to do this: @hash. <lang wortel>@hash ["a" "b" "c"] [1 2 3] ; returns {a 1 b 2 c 3}</lang> This function can also be defined as: <lang wortel>^(@obj @zip)</lang> Example: <lang wortel>@let {
hash ^(@obj @zip) !!hash ["a" "b" "c"] [1 2 3]
}</lang>

Returns:
{a 1 b 2 c 3}
zkl
<lang zkl>keys:=T("a","b","c","d"); vals:=T(1,2,3,4); d:=keys.zip(vals).toDictionary(); d.println(); d["b"].println();</lang>

Output:
D(a:1,b:2,c:3,d:4) 2

Icon and Unicon

Iterative

Iterative Using Foreach

Using Reduce

MATLAB / Octave

MATLAB/Octave: structs

MATLAB only: containers.Map

REXX Style

Java Collections

One-liner, using quasiquoted hash syntax

One-liner, using hash-construct function

Explicit construction and stuffing

One-liner, using `hash-construct` function