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Javascript - array.contains(obj)
Best way to find an item in a JavaScript Array ?
I want to check, for example, for the word "the" in a list or map. Is there is any kind of built in function for this?
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See the linked question for some very good answers.Andrzej Doyle– Andrzej Doyle2011-03-09 12:21:30 +00:00Commented Mar 9, 2011 at 12:21
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1Javascript doesn't have "lists" or "maps". It has arrays and objects.Lightness Races in Orbit– Lightness Races in Orbit2011-03-09 12:27:38 +00:00Commented Mar 9, 2011 at 12:27
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2 Answers
In javascript you have Arrays (lists) and Objects (maps).
The literal versions of them look like this:
var mylist = [1,2,3]; // array
var mymap = { car: 'porche', hp: 300, seats: 2 }; // object
if you which to figure out if a value exists in an array, just loop over it:
for(var i=0,len=mylist.length;i<len;i++) {
if(mylist[i] == 2) {
//2 exists
break;
}
}
if you which to figure out if a map has a certain key or if it has a key with a certain value, all you have to do is access it like so:
if(mymap.seats !== undefined) {
//the key 'seats' exists in the object
}
if(mymap.seats == 2) {
//the key 'seats' exists in the object and has the value 2
}
Comments
Array.indexOf(element) returns -1 if element is not found, otherwise returns its index
1 Comment
Human Being
The indexOf() method is not supported in Internet Explorer 8 and earlier.