Loop through array then do something after last occurrence

Question

I am trying to loop through an array. The array is basically a list from a .txt file on a server, which looks like this:

12345|Test message
55555|55555's message
12345|Test message 2

I do a simple GET request to the server, then get the response in a variable called res. I then do this:

array = res.split("\n");

for(i = 0; i < array.length; i++) {
    array2 = array[i].split("|");
    if(array2[0] == "12345") {
        console.log(array[1]);
    }
}

It will go through each line of the array, split it on | and then check if the first "element" is 12345. If it is, then write the message in the console. However, I want it to write the last message and not every message. In this case, it will write:

Test message
Test message 2

But I want it to write

Test message 2

The "question" is: Can you loop through the array, but only do something after it has found the last message? Thanks.

Mark Reed · Accepted Answer · 2014-10-23 13:41:52Z

3

Just store the message in a variable and output it after the loop.

array = res.split("\n");

var logMe;
for(i = 0; i < array.length; i++) {
  array2 = array[i].split("|");
  if(array2[0] == "12345") {
    logMe = array[1];
  }
}
if (logMe) {
  console.log(logMe)
}

answered Oct 23, 2014 at 13:41

Mark Reed

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2 Comments

MortenMoulder Over a year ago

Oh why didn't I think about that... The message in the variable will just get replaced each time it runs then. Thanks for clearing up my head!

MortenMoulder Over a year ago

Maybe you can answer this question as well. I want to dismiss the message (it shows itself in a nice box with a dismiss button) but I can't figure out if this is the best way... I basically set a local storage variable "dismiss" to false when the message is shown. When pressing dismiss, set dismiss var to true. On next page load, it checks for new messages, and if the new message != the old stored message, then show it. Do you have any better ideas? Obviously store the old message in a local storage variable so it can be grabbed on other pages.

user2075886 · Accepted Answer · 2014-10-23 13:48:50Z

2

Or you can simply go through the array backwards :)

array = res.split("\n");

var i = array.length;
for(i; i > 0; i--) {
    array2 = array[i].split("|");
    if(array2[0] == "12345") {
        console.log(array[1]);
        break;
    }
}

(exactly your code, just backwards + break; if there is no point observing other lines)

answered Oct 23, 2014 at 13:48

user2075886

1035 bronze badges

1 Comment

MortenMoulder Over a year ago

That's pretty much what I asked actually. I find Mark's idea a bit better, but definitely does the job.

DysphoricUnicorn · Accepted Answer · 2014-10-23 13:44:18Z

-1

This should do it:

for(i = 0; i < array.length; i++) {
array2 = array[i].split("|");
if(array2[0] == "12345") {
    console.log(array[1]);
}
if(i == array.lenght - 1){
System.out.println("Message2");
}

answered Oct 23, 2014 at 13:44

DysphoricUnicorn

5628 silver badges18 bronze badges

2 Comments

Mark Reed Over a year ago

I think you misunderstood the question.

DysphoricUnicorn Over a year ago

sorry i mixed up java and javaskript

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