Question

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Javascript compare items in one array

rated 0 times [ 1] [ 3] / answers: 1 / hits: 43577 / 12 Years ago, mon, june 18, 2012, 12:00:00

Pardon my complete lack of javascript knowledge in advance, but I can't seem to find a good example of how to compare two arrays and create another array based the results.

I am attempting to get a list of user accounts from a storage device (uses javascript and handles MOST functions ok), and compare them against a statically created list of good users.

Using a switch statement works but I really do not like it, and I'm sure there is a much better way (userList is populated dynamically from the device when I query it):

for (userName = 0; userName < userList.length; userName++) {

    switch (userList[userName]) {

    case 'someuser1':

            printf('Username: ' + userList[userName] + ' is goodn');

            break;

    case 'someuser2':

            printf('Username: ' + userList[userName] + ' is goodn');

            break;

    case 'someuser3':

            printf('Username: ' + userList[userName] + ' is goodn');

            break;

    default:

            printf('Username: ' + userList[userName] + ' is NOT goodn');

    } 

}

I would like to create a third array of bad users and compare them against a new array of good users, and found users. I have started with:

var goodUsers = [someuser1, someuser2, someuser3];

However I can't figure out the right combination of multiple for loops, if statements, or otherwise to compare the two and give me an array of the bad users that I can loop through and perform actions against.

Any help would be appreciated!

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markusdamienn

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1 Year ago

answered 12 Years ago shylaelisan · Accepted Answer

Array's indexOf method is sweet. It returns the position of an element in the array, if it exists, or returns -1 if it does not.

var goodUsers = [someuser1, someuser2, someuser3];

var users = [someuser1, 'basuser'];

var user;



for (var i=0; i < users.length; i++) {

  user = users[i];

  if (goodUsers.indexOf(user) >= 0) {

    console.log(user + ' is a good user');

  } else {

    console.log(user + ' is BAD!!!');

  }

}

http://jsfiddle.net/qz5fx/1