I need to search for the presence of an array inside an array. It is similar to jQuery.inArray function.
For
var a = [ [1,2], [1,3] ];
console.log( jQuery.inArray([1,3],a ) )
I get -1 as ans. How to do this?
Thank you
Add a comment
|
3 Answers
In V8 (that is, Chrome), there is a nifty trick: while == does not work for arrays, <= && >= does.
You can iterate and check for each item if it's appearent:
for(var i = 0; i < a.length; i++) {
if(a[i] >= [1, 3] && a[i] <= [1, 3]) alert(i);
}
For other browsers, you'd need a function that checks for array equality:
http://www.svendtofte.com/code/usefull_prototypes/prototypes.js
Array.prototype.compareArrays = function(arr) {
if (this.length != arr.length) return false;
for (var i = 0; i < arr.length; i++) {
if (this[i].compareArrays) { //likely nested array
if (!this[i].compareArrays(arr[i])) return false;
else continue;
}
if (this[i] != arr[i]) return false;
}
return true;
}
Then:
for(var i = 0; i < a.length; i++) {
if(a[i].compareArrays([1, 3])) alert(i);
}
Comments
function inArray (needle, haystack) {
for (var idx in haystack) {
if (haystack[idx].join(',') == needle.join(','))
return idx;
}
return -1;
}
1 Comment
pimvdb
Nice but
[[1,2],3].join(",") === [1,[2,3]].join(",") so it's not 100% reliable.try this
function look4arr(arr, v) {
for (var i = 0, l = arr.length; i < l; i += 1) {
if (arr[i].toString() === v.toString()) { //or use +''
return true;
}
}
return false;
}
var a = [[1,2], 2],
ok = [1,2],
ko = [2,3]
look4arr(a, ok); // true
look4arr(a, ko); // false
// as far as the array you are looking at contains primitives seem to work fine
if you need to search for something "more" ...I mean object literals, regexp, functions You could use a function similar to the following one
function look4x(arr, v) {
for (var i = 0, isObjOrArray = false, l = arr.length; i < l; i += 1) {
isObjOrArray = {}.toString.call(arr[i]).match(/\[object\s(Array|Object)\]/);
if (
(isObjOrArray && JSON.stringify(arr[i])+'' == JSON.stringify(v)+'' )
||
(!isObjOrArray && arr[i].toString() === v.toString())
) {
return true;//or i if a jQuery.inArray output is needed
}
}
return false; // or -1 ... if ... jQuery.inArray
}
var a = [
[1,[1,[1,[1,2]]]],
2,
true,
'hei',
Infinity,
{"o" : "s", 'd':[1,2,3]},
new RegExp(/\s/),
function(){alert('hei');}
],
ok = [1,[1,[1,[1,2]]]];
alert(
look4x(a, [1,[1,[1,[1,2]]]])
&&
look4x(a, true)
&&
look4x(a, 'hei')
&&
look4x(a, Infinity)
&&
look4x(a, {"o" : "s", 'd':[1,2,3]})
&&
look4x(a, new RegExp(/\s/))
&&
look4x(a, function(){alert('hei');})
); // true, in this case
Please note that I didn`t tested it yet with a complete test; I'll post a test asap
Event if I seem to be late, hope it can help someone.
Bye
1 Comment
fedeghe
ok, now behave correctly searching for array with object literals