Hash from two arrays
You are encouraged to solve this task according to the task description, using any language you may know.
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
ActionScript
<lang actionscript>package {
public class MyClass { public static function main():Void { var hash:Object = new Object(); var keys:Array = new Array("a", "b", "c"); var values:Array = new Array(1, 2, 3); for (var i:int = 0; i < keys.length(); i++) hash[keys[i]] = values[i]; } }
}</lang>
Ada
<lang ada>with Ada.Strings.Hash; with Ada.Containers.Hashed_Maps; with Ada.Text_Io; with Ada.Strings.Unbounded; use Ada.Strings.Unbounded;
procedure Hash_Map_Test is
function Equivalent_Key (Left, Right : Unbounded_String) return Boolean is begin return Left = Right; end Equivalent_Key; function Hash_Func(Key : Unbounded_String) return Ada.Containers.Hash_Type is begin return Ada.Strings.Hash(To_String(Key)); end Hash_Func; package My_Hash is new Ada.Containers.Hashed_Maps(Key_Type => Unbounded_String, Element_Type => Unbounded_String, Hash => Hash_Func, Equivalent_Keys => Equivalent_Key); type String_Array is array(Positive range <>) of Unbounded_String; Hash : My_Hash.Map; Key_List : String_Array := (To_Unbounded_String("foo"), To_Unbounded_String("bar"), To_Unbounded_String("val")); Element_List : String_Array := (To_Unbounded_String("little"), To_Unbounded_String("miss"), To_Unbounded_String("muffet"));
begin
for I in Key_List'range loop Hash.Insert(Key => (Key_List(I)), New_Item => (Element_List(I))); end loop; for I in Key_List'range loop Ada.Text_Io.Put_Line(To_String(Key_List(I)) & " => " & To_String(Hash.Element(Key_List(I)))); end loop;
end Hash_Map_Test;</lang>
Argile
<lang Argile>use std, array, hash
let keys = @["hexadecimal" "decimal" "octal" "binary"] let values = @[0xa 11 014 0b1101] (: 10 11 12 13 :) let hash = new hash of int for each val int i from 0 to 3
hash[keys[i]] = values[i]
del hash hash</lang>
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>$ awk 'BEGIN{split("one two three",a);
split("1 2 3",b); for(i=1;i in a;i++){c[a[i]]=b[i]}; for(i in c)print i,c[i] }'
three 3 two 2 one 1</lang>
BASIC256
Solution is at Associative_array/Creation#BASIC256.
BBC BASIC
<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>
C
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, ©Str, ©Int, &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>
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
<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>import std.array, std.range;
void main() {
auto 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>
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 harbour> Local arr1 := { 6, "eight" }
Local arr2 := { 16, 8 } Local arr := hb_Hash(), i, x
FOR i := 1 TO Len( arr1 ) hb_hSet( arr, arr1[i], arr2[i] ) NEXT</lang>
Haskell
<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
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 at random 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
<lang javascript>var keys = ['a', 'b', 'c']; var values = [1, 2, 3]; var map = {}; for(var i in keys) {
map[ keys[i] ] = values[i];
}</lang>
Julia
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>
Lua
<lang lua> function(keys,values)
local t = {} for i=1, #keys do t[keys[i]] = values[i] end
end </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>
NetRexx
REXX Style
<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>
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>
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 </lang>
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>
Pascal
<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
<lang perl>my @keys = qw(a b c); my @vals = (1, 2, 3); my %hash; @hash{@keys} = @vals;</lang>
Alternatively, using
:
<lang perl>use List::MoreUtils qw(zip); my %hash = zip @keys, @vals;</lang>
Perl 6
<lang perl6>my @keys = <a b c d e>; my @vals = ^5; my %hash = @keys Z @vals;</lang>
or just
<lang perl6>my @v = <a b c d e>; my %hash = @v Z @v.keys;</lang>
Alternatively:
<lang perl6>my %hash; %hash{@keys} = @vals;</lang>
To create an anonymous hash value, you can use Z as a "zipwith" metaoperator on the => pair composer:
<lang perl6>{ <a b c d e> Z=> ^5 }</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 }</lang> This will fail if the lists differ in length.
PHP
<lang php>$keys = array('a', 'b', 'c'); $values = array(1, 2, 3); $hash = array_combine($keys, $values);</lang>
<lang php>$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
<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
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>
<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>
<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
<lang racket> (make-hash (map cons '("a" "b" "c" "d") '(1 2 3 4)))</lang>
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 demonstrate 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'
/*superflous blanks added to humorous keys just 'cause it looks prettier*/ call hash values,keys /*hash the keys to the values. */ parse arg query . /*what was specified on cmd line.*/ if query== then exit /*nothing, then let's leave Dodge*/ pad=left(,30) /*used for padding the display. */ say 'key:' query pad "value:" hash.query /*show & tell 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]
if RUBY_VERSION >= '1.8.7'
# Easy way, but needs Ruby 1.8.7 or later. hash = Hash[keys.zip(vals)]
else
hash = keys.zip(vals).inject({}) {|h, kv| h.store(*kv); h }
end
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".
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>
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>
<lang smalltalk>Dictionary
withKeys:#('one' 'two' 'three') andValues:#('eins' 'zwei' 'drei')</lang>
<lang smalltalk>Dictionary withAssociations:{ 'one'->1 . 'two'->2 . 'three'->3 }</lang>
SNOBOL4
<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
Standard ML
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>
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>
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 }</lang> Alternatively, a dictionary could be used: <lang tcl>foreach a $keys b $values {
dict set jobs $a $b
}</lang>
TXR
<lang txr>@(do (defun hash-from-two (vec1 vec2 equal-based-p)
(let ((table (make-hash nil nil equal-based-p))) (for ((i 0)) ((< i (length vec1)) table) ((inc i)) (set (gethash table (vecref vec1 i) 0) (vecref vec2 i))))))
@(bind hash @(hash-from-two #(a b c) #(1 2 3) nil)) @(bind (keys vals) @(let (k v)
(dohash (key val hash (list k v)) (push key k) (push val v))))</lang>
$ ./txr rosetta/hash-from-two.txr hash="#<hash: 175bc40>" keys[0]="a" keys[1]="b" keys[2]="c" vals[0]="1" vals[1]="2" vals[2]="3"
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>
Ursala
There's 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
<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
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:=Utils.zipWith(Void,keys,vals).toDictionary(); d.println(); d["b"].println()</lang>
- Output:
D(a:1,b:2,c:3,d:4) 2
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