php foreach loop with continue if value has already been echoed

Question

I have a foreach loop and I need to add a continue if the value has already been echoed. I can't find the right syntax. The loop:

foreach ($results as $result) {
   echo $result->date . "<br />"; 
}

But I need to add in a continue so that if the value has already been echoed, and it comes up again in the loop it gets skipped. I can't quite get the if/continue statement quite right.

Thoughts, suggestions, ideas?

Typically you would add the date to an array as you echo each one and if in_array continue. — Jonathan Kuhn
– Jonathan Kuhn, Commented Sep 18, 2014 at 21:18
Depending on the nature of a single $result, $results = array_unique($results) before the loop might also help. — andy
– andy, Commented Sep 18, 2014 at 21:22
@CharlotteDunois I can see that. However, if the object implements __toString() the right way, it would work and result in IMO readable code. — andy
– andy, Commented Sep 18, 2014 at 21:25

Dan · Accepted Answer · 2014-09-18 21:21:55Z

5

As mentioned by @JonathanKuhn in the comments - here is how you would run that loop:

$already_echoed = array();
foreach ($results as $result) {
    if (!in_array($result->date, $already_echoed)) { //check if current date is in the already_echoed array
        echo $result->date . "<br />";   
    }
    $already_echoed[] = $result->date; //store all dates in an array to check against.
}

answered Sep 18, 2014 at 21:21

Dan

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9 Comments

Charlotte Dunois Over a year ago

Either you forgot to echo the date or implode and echo the array.

tatorface Over a year ago

Off topic, is $array[] = $adding_item the preferred method of adding to an array? I always use array_push().

Dan Over a year ago

@tatorface $array[] preferred - see reference stackoverflow.com/questions/1074059/…

Dan Over a year ago

Instead of posting the code here edit your question - it's too difficult to make sense of it in the comment.

tatorface Over a year ago

@Dan thanks, I did the test on your linked page and it $array[] is by far and away the quicker tool. Thanks for your help.

|

Tengiz · Accepted Answer · 2014-09-18 21:33:58Z

2

$echoedArray = array();
foreach ($results as $result) {
    if (isset($echoedArray[$result->date])) {
        continue;
    }
    echo $result->date . "<br />";
    $echoedArray[$result->date] = true;
}

edited Sep 18, 2014 at 21:33

answered Sep 18, 2014 at 21:23

Tengiz

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4 Comments

Tengiz Over a year ago

Be aware. in_array is much slower function rather than check by the key

Charlotte Dunois Over a year ago

in_array is not much slower. And this little difference doesn't really matter. 3v4l.org/nQZbc

Tengiz Over a year ago

well, it would matter if you had hundreds thousands of elements

Charlotte Dunois Over a year ago

On HHVM-3.1 in_array() is even faster with 1000 elements. (:

Ahamad I Milazi · Accepted Answer · 2014-09-18 21:28:58Z

1

    $alreadyOutput = array();
    foreach ($results as $result) {
       if(in_array($result->date, $alreadyOutput)){
           continue;
       }
       $alreadyOutput[] = $result->date; 
       echo $result->date . "<br />";
    }

answered Sep 18, 2014 at 21:28

Ahamad I Milazi

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