I need to compare four variables.if any two variables are same i need show an alert. i did like the following way.
var a =1;
var b =2;
var c =3;
var d =4;
if((a==b)||(a==c)||(a==d)||(b==c)||(b==d)||(c==d)){
alert("Value is same, Please change the value");
return false;
}
Is that possible to reduce the expression to one condition instant of checking all the variables separately.Kindly advice ... TnQ in advance.
well, i'll toss this into the ring, albeit it is likely not the right approach to this but it is fun. (note: browser compatibility issues and possibly over-kill is about to precede)
var a = 1,
b = 2,
c = 1,
d = 3;
[a, b, c, d].sort(function(a, b) {
return a - b;
}).reduce(function(a, b) {
if (a == b) {
alert('HERE');
}
return b;
});
demo here:
http://jsfiddle.net/rlemon/Eu4qG/
further readings:
Array.reduce
Array.sort
while is enough. This will work on any length of array. But the a array will be modified, you may need to duplicate.
a = [1, 2, 3, 4];
while (a.length > 1)
if (a.indexOf(a.pop()) != -1) {
alert("Value is same, Please change the value");
break;
}
My previous answer (in revision), which using for, was little embarrassing.
This checks to see if any of the values are the same as any of the other values:
var values = [a, b, c, d, e, f /* ... */];
function shared_values(values) {
for (var i = 0; i < values.length; i++) {
for (var j = i; j < values.length; j++) {
if (values[i] === values[j]) {
return true;
}
}
}
return true;
}
if (shared_values(values)) {
// Don't submit form or whatever
}
You could write a function to check them for you, maybe something like this:
EDIT: Based on other answers, you could make it more efficient with a sort
function areTwoEqual() {
var arg_list = [].slice.call(arguments).sort(
function(a,b) { return a-b; }
);
var vals = {};
for(var i = 0, len = arg_list.length; i < len; i++) {
if(vals[arg_list[i]]) {
return true;
}
vals[arg_list[i]] = '1';
}
return false;
}
var a =1;
var b =2;
var c =3;
var d =1;
if(areTwoEqual(a,b,c,d)) {
alert('Two values are identical!');
} else {
alert('all values are unique');
}
To avoid a comparison between the same element and itself
if (values[i] === values[j]) { }
I think that it should be upgraded to
if ( (values[i] === values[j]) && (i != j) ) { }
but thanks for the script
