JavaScript is in array

Question

Let s say I have this   var blockedTile   new Array  118    67    190    43    135    520      There s more array elements but those are just few for readability purposes  Anyways  I could do a  for  loop but it would do 500 loops everytime you click on the map    is there any other way to see if a certain string is in an array

User · Answer

Already answered above but wanted to share.

Will not work in IE though. thanks for mentioning it @Mahmoud

_x000D_

var array1 = [1, 2, 3];_x000D_
_x000D_
console.log(array1.includes(2));_x000D_
// expected output: true_x000D_
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var pets = ['cat', 'dog', 'bat'];_x000D_
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console.log(pets.includes('cat'));_x000D_
// expected output: true_x000D_
_x000D_
console.log(pets.includes('at'));_x000D_
// expected output: false

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got some reference Here. they also have Polyfill for above.

User · Answer

Assuming that you re only using the array for lookup  you can use a Set  introduced in ES6   which allows you to find an element in O 1   meaning that lookup is sublinear  With the traditional methods of  includes   and  indexOf    you still may need to look at all 500  ie  N  elements in your array if the item specified doesn t exist in the array  or is the last item    This can be inefficient  however  with the help of a Set  you don t need to look at all elements  and instead  instantly check if the element is within your set   x000D   x000D  const blockedTile   new Set   118    67    190    43    135    520      if blockedTile has  118           118 is in your Set   console log  Found 118      x000D   x000D   x000D   If for some reason you need to convert your set back into an array  you can do so through the use of Array from   or the spread syntax        however  this will iterate through the entire set s contents  which will be O N    Sets also don t keep duplicates  meaning that your array won t contain duplicate items

User · Answer

function in array needle  haystack       var found   0      for  var i 0  len haystack length i lt len i              if  haystack i     needle  return i              found              return -1    if in array  118  array    -1     is in array

User · Answer

Just use for your taste    x000D   x000D  var blockedTile    118  67  190  43  135  520   x000D   x000D     includes  js  x000D   x000D  if   blockedTile includes 118     x000D      console log  Found with  includes     x000D    x000D   x000D     indexOf  js  x000D   x000D  if   blockedTile indexOf 67      -1    x000D      console log  Found with  indexOf     x000D    x000D   x000D       indexOf  Underscore library  x000D   x000D  if     indexOf blockedTile  43  true     x000D      console log  Found with Underscore library    indexOf     x000D    x000D   x000D       inArray  jQuery library  x000D   x000D  if     inArray 190  blockedTile      -1    x000D      console log  Found with jQuery library    inArray     x000D    x000D   lt script src  https   cdnjs cloudflare com ajax libs underscore js 1 8 3 underscore-min js  gt  lt  script gt  x000D   lt script src  https   ajax googleapis com ajax libs jquery 2 1 1 jquery min js  gt  lt  script gt  x000D   x000D   x000D

User · Answer

Depending on the version of JavaScript you have available  you can use indexOf      Returns the first index at which a given element can be found in the array  or -1 if it is not present    Or some      Tests whether some element in the array passes the test implemented by the provided function    But  if you re doing this sort of existence check a lot you d be better of using an Object to store your strings  or perhaps an object as well as the Array depending on what you re doing with your data

User · Answer

in array example Its same in php  in array      var ur fit     slim fit    tailored    comfort     var ur length     length short    length regular    length high        if ur fit indexOf data this   -1           alert  Value is avail in ur fit array              else if ur length indexOf data this   -1                  alert  value is avail in ur legth array

User · Answer

Why don t you use Array filter   var array     x   y   z    array filter function item index array  return item  YOURVAL       Just copy that into your code  and here you go   Array prototype inArray   function  searchedVal    return this filter function item index array  return item  searchedVal    length  true

User · Answer

if array indexOf  67      -1     is in array

User · Answer

var myArray    2 5 6 7 9 6   myArray includes 2     is true myArray includes 14     is false

User · Answer

Use Underscore js  It cross-browser compliant and can perform a binary search if your data is sorted      indexOf       indexOf array  value   isSorted    Returns the index at which value can be found in the array  or -1 if value is not present in the array    Uses the native indexOf function unless it s missing  If you re   working with a large array  and you know that the array is already   sorted  pass true for isSorted to use a faster binary search    Example    Tell underscore your data is sorted  Binary Search  if   indexOf   2   3   4   5   6     4   true     -1       alert  true     else      alert  false            Unsorted data works to  if   indexOf  2 3 6 9 5   9     -1       alert  true     else      alert  false

User · Answer

I think the simplest way is that     118 in blockedTile     is true

User · Answer

Best way to do it in 2019 is by using  includes     1  2  3  includes 2          true  1  2  3  includes 4          false  1  2  3  includes 1  2       false   First parameter is what you are searching for  Second parameter is the index position in this array at which to begin searching   If you need to be crossbrowsy here - there are plenty of legacy answers

User · Answer

IMHO most compatible with older browsers  Array prototype inArray   function  needle         return Array this  join      indexOf needle   gt -1      var foods     Cheese   Onion   Pickle   Ham    test   foods inArray  Lemon    console log   Lemon is      test         not       in the list        By turning an Array copy in to a CSV string  you can test the string in older browsers

User · Answer

I d use a different data structure  since array seem to be not the best solution   Instead of array  use an object as a hash-table  like so    posted also in jsbin   var arr     x    y    z    var map       for  var k 0  k  lt  arr length    k      map arr k     true     function is in map key      try       return map key      true      catch  e        return false          function print check key      console log key     exists  -      is in map key     yes     no        print check  x    print check  a      Console output   x exists  - yes a exists  - no   That s a straight-forward solution  If you re more into an object oriented approach  then search Google for  js hashtable

User · Answer

You can try below code  Check http   api jquery com jquery grep   var blockedTile   new Array  118    67    190    43    135    520    var searchNumber    11878   arr   jQuery grep blockedTile  function  i       return i     searchNumber      if arr length   console log  Present     else  console log  Not Present        check arr length if it s more than 0 means string is present else it s not present

User · Answer

Some browsers support Array indexOf     If not  you could augment the Array object via its prototype like so     if   Array prototype indexOf      Array prototype indexOf   function searchElement     fromIndex              use strict        if  this     void 0    this     null        throw new TypeError         var t   Object this       var len   t length  gt  gt  gt  0      if  len     0        return -1       var n   0      if  arguments length  gt  0              n   Number arguments 1          if  n     n     shortcut for verifying if it s NaN         n   0        else if  n     0  amp  amp  n      1   0   amp  amp  n     - 1   0           n    n  gt  0    -1    Math floor Math abs n               if  n  gt   len        return -1       var k   n  gt   0             n             Math max len - Math abs n   0        for    k  lt  len  k                if  k in t  amp  amp  t k      searchElement          return k            return -1           Source

User · Answer

Try this   if blockedTile indexOf  118      -1            element found

User · Answer

a little bit code from my side  custom function for Array       Array prototype in array   function  array            var  i   0          var type   typeof array          while  this  i                 if   type      number      type      string      amp  amp  array    this  i                     return true                else if  type     object   amp  amp  array instanceof Array  amp  amp  array in array this  i                      return true                            i                      return false               var array    1  2  3   quot a quot    quot b quot    quot c quot           if string in array     if  array in array  b              console log  quot in array quot                 if number in array     if  array in array 3             console log  quot in array quot                  if one from array in array     if  array in array  1   b               console log  quot in array quot

User · Answer

As mentioned before  if your browser supports indexOf    great   If not  you need to pollyfil it or rely on an utility belt like lodash underscore   Just wanted to add this newer ES2016 addition  to keep this question updated    Array prototype includes    if  blockedTile includes  118             found element

[javascript] JavaScript is in array

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