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up vote 0 down vote favorite

Just to illustrate what I want to do I'll pase this sample code for example:

<html>
<head>
</head>
<body>
<script type="text/javascript">
function oc(a)
{
  var o = {};
  for(var i=0;i<a.length;i++)
  {
    o[a[i]]='';
  }
  return o;
}
if ( "Island" in oc(["Hello","Hello World","Have","Island"]) )
{
document.write("Yes");
}
</script>
</body>
</html>

In this case I get Yes on my page, but if I change the condition like:

if ( "Isl" in oc(["Hello","Hello World","Have","Island"]) )

the function doesn't find match. What is the best way to perform such kind of check which will return true even if only part of the string match?

Thanks

Leron

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Javascript is not Python. I suggest you try to drop that "in" hack of yours... – missingno May 15 '12 at 17:42

4 Answers

up vote 3 down vote accepted

Use .indexOf():

var str = 'hello world'
if (str.indexOf('lo') >= 0) {
    alert('jippy');
}

indexOf() returns the position where the value is found. If there is no match it returns -1 so we need to check if the result is greater or equal to 0.

share|improve this answer
Here is a useful reference for String.indexOf(str) on MDN. – maerics May 15 '12 at 17:41
Thanks, very fast and very useful! – Leron May 15 '12 at 17:43
you could also use the String .match() method and check for true, but this is will run faster. – ZanderKruz May 15 '12 at 17:43
@maerics thank you. I was looking for some docs. – Wouter J May 15 '12 at 17:44
1  
if you need case insensitivity, you can use .toLowerCase() on str, e.g. if (str.toLowerCase().indexOf('lo')) {. – D. Strout May 15 '12 at 17:45
up vote 1 down vote

You can use .test method from regexes.

var pattern = /Isl/;
pattern.test("Island"); // true
pattern.test("asdf"); //false
share|improve this answer
Also a good one, thanks – Leron May 15 '12 at 17:45
up vote 0 down vote 
var s = "helloo";
alert(s.indexOf("oo") != -1);

indexOf returns the position of the string in the other string. If not found, it will return -1.

https://developer.mozilla.org/en/Core%5FJavaScript%5F1.5%5FReference/Objects/String/indexOf

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up vote 0 down vote 
<html> 
<head> 
</head> 
<body> 
<script type="text/javascript"> 
function inArray(str, array) 
{ 
  for(var i=0; i<array.length; i++) 
  { 
    if (array[i].indexOf(str) >= 0)
        return true;
  } 
  return false;
} 
if ( inArray("Island", ["Hello","Hello World","Have","Island"] ) 
{ 
document.write("Yes"); 
} 
</script> 
</body> 
</html>
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