How to find the array index with a value

Question

Say I ve got this  imageList    100 200 300 400 500     Which gives me   0 100  1 200 etc   Is there any way in JavaScript to return the index with the value   I e  I want the index for 200  I get returned 1

User · Answer

Array indexOf doesnt work in some versions of internet explorer - there are lots of alternative ways of doing it though     see this question   answer   How do I check if an array includes an object in JavaScript

User · Answer

You can use indexOf   var imageList    100 200 300 400 500   var index   imageList indexOf 200      1   You will get -1 if it cannot find a value in the array

User · Answer

When the lists aren t extremely long  this is the best way I know   function getIndex val        for  var i   0  i  lt  imageList length  i              if  imageList i      val                return i                     var imageList    100  200  300  400  500   var index   getIndex 200

User · Answer

how about indexOf     alert imageList indexOf 200

User · Answer

For objects array use map with indexOf    x000D   x000D  var imageList     x000D      value  100   x000D      value  200   x000D      value  300   x000D      value  400   x000D      value  500  x000D     x000D   x000D  var index   imageList map function  img    return img value     indexOf 200   x000D   x000D  console log index   x000D   x000D   x000D      In modern browsers you can use findIndex    x000D   x000D  var imageList     x000D      value  100   x000D      value  200   x000D      value  300   x000D      value  400   x000D      value  500  x000D     x000D   x000D  var index   imageList findIndex img   gt  img value     200   x000D   x000D  console log index   x000D   x000D   x000D    Its part of ES6 and supported by Chrome  FF  Safari and Edge

User · Answer

Instead Of  var index   arr indexOf 200      Use  var index   arr includes 200     Please Note  Includes function is a simple instance method on the array and helps to easily find if an item is in the array including NaN unlike indexOf

User · Answer

Here is an another way find value index in complex array in javascript  Hope help somebody indeed  Let us assume we have a JavaScript array as following   var studentsArray                     rollnumber   1       name    dj        subject    physics                 rollnumber   2     name    tanmay      subject    biology                rollnumber   3      name    amit       subject    chemistry               Now if we have a requirement to select a particular object in the array  Let us assume that we want to find index of student with name Tanmay   We can do that by iterating through the array and comparing value at the given key   function functiontofindIndexByKeyValue arraytosearch  key  valuetosearch         for  var i   0  i  lt  arraytosearch length  i           if  arraytosearch i  key     valuetosearch        return i                  return null          You can use the function to find index of a particular element as below   var index   functiontofindIndexByKeyValue studentsArray   name    tanmay    alert index

User · Answer

In a multidimensional array   Reference array  var array           ID   100            ID   200            ID   300            ID   400            ID   500         Using filter and indexOf  var in array   array filter function item         return item ID     200     look for the item where ID is equal to value     var index   array indexOf in array 0     Looping through each item in the array using indexOf  for  var i   0  i  lt  array length  i          var item  array i       if  item ID     200              var index   array indexOf item

User · Answer

It is possible to use a ES6 function Array prototype findIndex   MDN says      The findIndex   method returns the index of the first element in the array that satisfies the provided testing function  Otherwise -1 is returned    var fooArray    5  10  15  20  25   console log fooArray findIndex num  gt    return num  gt  5           expected output  1   Find an index by object property   To find an index by object property   yourArray findIndex obj   gt  obj  propertyName       yourValue    For example  there is a such array   let someArray           property   OutDate           property   BeginDate          property   CarNumber           property   FirstName        Then  code to find an index of necessary property looks like that   let carIndex   someArray findIndex  filterCarObj  gt       filterCarObj  property        CarNumber

User · Answer

Use jQuery s function jQuery inArray  jQuery inArray  value  array    fromIndex      or    inArray  value  array    fromIndex

User · Answer

Use indexOf  imageList indexOf 200

User · Answer

Here is my take on it  seems like most peoples solutions don t check if the item exists and it removes random values if it does not exist   First check if the element exists by looking for it s index  If it does exist  remove it by its index using the splice method  elementPosition   array indexOf value    if elementPosition    -1      array splice elementPosition  1

[javascript] How to find the array index with a value?

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