在javascript数组中寻找价值

Question

I'm trying to set up an IF statement if a value is contained within an array.

I've found some code which claimed to work but it doesn't seem to be.

var myAsi = ['01','02','24OR01','30De01','9thC01','A.Hu01','A01','AACAMSTE','ABBo01','ABBo02','ABC-01','ACCE01','Acce02','AceR01','h+dm01','Merr02','Ofak01','Wage01','Youn01'];

Array.prototype.find = function(searchStr) {
  var returnArray = false;
  for (i=0; i<this.length; i++) {
    if (typeof(searchStr) == 'function') {
      if (searchStr.test(this[i])) {
        if (!returnArray) { returnArray = [] }
        returnArray.push(i);
      }
    } else {
      if (this[i]===searchStr) {
        if (!returnArray) { returnArray = [] }
        returnArray.push(i);
      }
    }
  }
  return returnArray;
}

var resultHtml = '';
resultHtml+='<table style ="width: 400px">';
resultHtml+='<tr colspan="2">';
resultHtml+='<td colspan="2">';
resultHtml+='<b><font color = "Red">(Client Code)</font><br><font color = "green">(Company Name)</font></b>';
resultHtml+='</td>';
resultHtml+='</tr>';

$.each(data, function(i,item){
  resultHtml+='<div class="result">';
  resultHtml+='<tr>';
  if (notFound=myAsi.find("'"+item.code+"'") == false) {
    resultHtml+='<td>';
  }
  else {
    resultHtml+='<td bgcolor=#D8D8D8>';
  }
  resultHtml+='<font color = "red">'+item.code+'</font><br>';
  resultHtml+='<font color = "green">'+item.content+'</font></td>';
  resultHtml+='<td style ="width: 80px"><a href="delete.php?UserID=<?php echo $userID ?>&AddCode='+item.code+'">Remove</a> - ';
  resultHtml+='<a href="insert.php?UserID=<?php echo $userID ?>&AddCode='+item.code+'">Add</a>';
  resultHtml+='</td>';
  resultHtml+='</tr>';
  resultHtml+='</div>';
  });
resultHtml+='</table>';

The item.code cycles through and I need an IF statement to tell me if it appears within the array.

Any help would be great.

Answer 1

Try removing the apostrophes from your find() call. eg

notFound=myAsi.find(item.code)

Though actually, for your purposes see this example which uses this function....

Array.prototype.find = function(searchStr) {
       for (var i=0; i<this.length; i++) {
           if (this[i]==searchStr) return true;
       };
     return false;    
    };

And as an aside - Be very careful about using var before using a variable - otherwise you create a global variable (which you probably don't want). ie the line in your original function....

for (i=0; i<this.length; i++)

i is now global...

Answer 2

If you only want to find if an item is in an array you could use a simpler function than that. For eg. the jQuery implementation:

// returns index of the element or -1 if element not present
function( elem, array ) {
    if ( array.indexOf ) {
        return array.indexOf( elem );
    }
    for ( var i = 0, length = array.length; i < length; i++ ) {
        if ( array[ i ] === elem ) {
            return i;
        }
    }
    return -1;
},

This uses the native browser implementation of indexOf if available (all browsers except IE I think), otherwise a manual loop.

Answer 3

Array.prototype.contains = function(value, matcher) {
    if (!matcher || typeof matcher !== 'function') {
        matcher = function(item) {
            return item == value;
        }
    }
    for (var i = 0, len = this.length; i < len; i++) {
        if (matcher(this[i])) {
            return true;
        }
    }
    return false;
};

This returns true for elements in the array that statisfy the conditions defined in matcher. Implement like this:

var arr = ['abc', 'def', 'ghi'];   // the array
var valueToFind= 'xyz';  // a value to find in the array

// a function that compares an array item to match
var matcher = function(item) {
    return item === matchThis;
};

// is the value found?
if (arr.contains(valueToFind, matcher)) {
    // item found 
} else {
    // item not found 
}

UPDATES: Changed the contains method to take a value and an optional matcher function. If no matcher is included, it will do a simple equality check.

Test this on jsFiddle.net: http://jsfiddle.net/silkster/wgkru/3/

Answer 4

You could just use the builtin function

['a','b','c'].indexOf('d') == -1

This behavior was mandated in the javascript specification from over 6 years ago. Though I gave up on Internet Explorer for these reasons at around IE8, because of this incredibly poor support for standards. If you care about supporting very old browsers, you can use http://soledadpenades.com/2007/05/17/arrayindexof-in-internet-explorer/ to tack on your own custom Array.indexOf

I don't recall IE9 supporting [].indexOf, but Microsoft claims it does: http://msdn.microsoft.com/en-us/library/ff679977(v=VS.94).aspx

Answer 5

The standard way to determine the index of the first occurence of a given value in an array is the indexOf method of Array objects.

This code checks if it this method is supported, and implements it if not, so that it is available on any Array object:

if(Array.prototype.indexOf==null)
Array.prototype.indexOf = function(x){
    for(var i=0, n=this.length; i<n; i++)if(this[i]===x)return i;
    return -1;
};

Now myArray.indexOf(myValue) returns the first index of myValue in myArray , or -1 if not found.