I have an array:
$arr1 = [1,2,2,3,3,3];
Is there any method by which I can delete a duplicate value once like,
some_function($arr1,3);
which gives me the ouput $arr1 = [1,2,2,3,3]
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1This is such a specific requirement that there isn't a built-in method. Count the number of instances in the array, if there are > 1 then find and remove one.JJJ– JJJ2017-10-20 07:32:35 +00:00Commented Oct 20, 2017 at 7:32
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@JJJ Yep you are right. But could you provide me with some more details?Irfan Sindhi– Irfan Sindhi2017-10-20 07:34:15 +00:00Commented Oct 20, 2017 at 7:34
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check answers below/Salim Ibrohimi– Salim Ibrohimi2017-10-20 08:02:12 +00:00Commented Oct 20, 2017 at 8:02
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3 Answers
As per the comment, check if there are more than one of the element you're searching for, then find and remove one of them.
function remove_one_duplicate( $arr, $target ) {
if( count( array_keys( $arr, $target ) ) > 1 ) {
unset( $arr[array_search( $target, $arr )] );
}
return $arr;
}
1 Comment
mickmackusa
As for this question, here's a slight refinement (replace
array_search() with current()) sandbox.onlinephpfunctions.com/code/…This should work...
function removeduplicate($myarray,$needle) {
if (($nmatches = count($matches = array_keys($myarray,$needle))) >= 2) {
for ($i=0; $i<$nmatches; $i++) {
if ($matches[$i+1] == (1+$matches[$i])) {
array_splice($myarray,$matches[$i],1);
break;
}
}
}
return $myarray;
}
To use the function...
$arr1 = [1,2,2,3,3,3,4,7,3,3];
$newarray = removeduplicate($arr1,3)
print_r($newarray);
EDITED:
If you want the function to modify your original array directly, you can do it (the function will return true if a character has been removed or false if not)...
function removeduplicate(&$myarray,$needle) {
if (($nmatches = count($matches = array_keys($myarray,$needle))) >= 2) {
for ($i=0; $i<$nmatches; $i++) {
if ($matches[$i+1] == (1+$matches[$i])) {
array_splice($myarray,$matches[$i],1);
return true;
}
}
}
return false;
}
So, now you can do...
$arr1 = [1,2,2,2,2,2,3,3,3,4,2,2];
removeduplicate($arr1,2);
print_r($arr1);
2 Comments
Sysix
I think if your make the first
if-condition as a while loop, you can actually match more then one duplicate number.
A. Iglesias
I've changed the approach. Thanks @Sysix!
This function will copy the array skipping only the second instance of the specified element.
function removeOnce($array, $elem) {
$found = 0;
$result = [];
foreach ($array as $x) {
if ($x == $elem && (++$found) == 2) {
continue;
}
$result[] = $x;
}
return $result;
}
1 Comment
mickmackusa
Unfortunately this method will do a lot of iterating to build the new array. A better / more efficient method would be to remove/unset one duplicate and break from the loop.