Javascript If statement, looking through an array - Stack Overflow

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Mind has gone blank this afternoon and can't for the life of me figure out the right way to do this:

if(i!="3" && i!="4" && i!="5" && i!="6" && i!="7" && i!="8" && i!="9" && i!="2" && i!="19" && i!="18" && i!="60" && i!="61" && i!="50" && i!="49" && i!="79" && i!="78" && i!="81" && i!="82" && i!="80" && i!="70" && i!="90" && i!="91" && i!="92" && i!="93" && i!="94"){

//do stuff

}

All those numbers need to be in an array, then I can check to see if "i" is not equal to any 1 of them.

Mind has gone blank this afternoon and can't for the life of me figure out the right way to do this:

if(i!="3" && i!="4" && i!="5" && i!="6" && i!="7" && i!="8" && i!="9" && i!="2" && i!="19" && i!="18" && i!="60" && i!="61" && i!="50" && i!="49" && i!="79" && i!="78" && i!="81" && i!="82" && i!="80" && i!="70" && i!="90" && i!="91" && i!="92" && i!="93" && i!="94"){

//do stuff

}

All those numbers need to be in an array, then I can check to see if "i" is not equal to any 1 of them.

• javascript
• if-statement

Share Improve this question Follow edited Oct 4, 2018 at 20:46 jjmontes 26.9k55 gold badges4343 silver badges5252 bronze badges asked Aug 6, 2010 at 15:30 Adam TomatAdam Tomat 11.5k66 gold badges4040 silver badges4848 bronze badges 3

• see stackoverflow.com/questions/237104/javascript-array-containsobj – fearofawhackplanet Commented Aug 6, 2010 at 15:33
• possible duplicate of Best way to find an item in a JavaScript Array ? – Evan Carroll Commented Aug 6, 2010 at 15:38
• 1 @fearofawhackplanet, you're right too. I've marked that function as a dupe as well. – Evan Carroll Commented Aug 6, 2010 at 15:40

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3 Answers 3

Sorted by: Reset to default 18

var a = [3,4,5,6,7,8,9];

if ( a.indexOf( 2 ) == -1 ) { 
   // do stuff
}

indexOf returns -1 if the number is not found. It returns something other than -1 if it is found. Change your logic if you want.

Wrap the numbers in quotes if you need strings ( a = ['1','2'] ). I don't know what you're dealing with so I made them numbers.

IE and other obscure/older browsers will need the indexOf method:

if (!Array.prototype.indexOf)  
{  
  Array.prototype.indexOf = function(elt /*, from*/)  
  {  
    var len = this.length >>> 0;  

    var from = Number(arguments[1]) || 0;  
    from = (from < 0)  
         ? Math.ceil(from)  
         : Math.floor(from);  
    if (from < 0)  
      from += len;  

    for (; from < len; from++)  
    {  
      if (from in this &&  
          this[from] === elt)  
        return from;  
    }  
    return -1;  
  };  
}  

My mind made this solution:

function not(dat, arr) { //"not" function
for(var i=0;i<arr.length;i++) {
  if(arr[i] == dat){return false;}
}
return true;
}

var check = [2,3,4,5,6,7,8,9,18,19,49,50,60,61,70,78,79,80,81,82,90,91,92,93,94]; //numbers

if(not(i, check)) {
//do stuff
}

This solution is cross-browser:

var valid = true;
var cantbe = [3, 4, 5]; // Fill in all your values
for (var j in cantbe)
    if (typeof cantbe[j] === "number" && i == cantbe[j]){
        valid = false;
        break;
    }

valid will be true if i isn't a 'bad' value, false otherwise.

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