PHP array comparision error

Question

I have 2 SELECT statement in my PHP. Both the select statements fetch data from two different DB. The fetched data is saved in PDO Assoc Array. The problem is when I want to compare those two arrays to find that if the column 'id' exist in both arrays or not. If it exists then ignore it. If it's a unique id then save it into a third array. But I found some problems in my Logic Below

And after running the below code I am getting a couple of error: 1: Array to string conversion 2: duplicate key value violates unique constraint

$arr1 = $msql->fetchAll(PDO::FETCH_ASSOC);
$array1 = array();
foreach($arr1 as $x){
$array1[] = $x['id'];
}


$arr2 = $psql->fetechAll(PDO::FETCH_ASSOC);
$array2 = array();
foreach($arr2 as $y){
  $array2[] = $y['id'];
 }

$finalarray = array();
for ($i = 0; $i < count($arr1); $i++){
if(count(array_intersect($array1,$array2)) <= 1){// is the count of id is 1 or less save that whole row in the $finalarray
      $finalarray = $arr1[$i]; // saving the unique row.
}
else{
    continue;
}
}

All I am trying to get the unique row of data array() after comparing their id column.

You had asked similar question here , should have edited the same question . Please delete older post now — Jigar Shah
– Jigar Shah, Commented Mar 8, 2018 at 5:52
The code runs fine after @Gufran Hasan fixed it. But the error comes when there is a duplicate already exist in the db while inserting the data which fails to execute the query completely. — sam scoot1900
– sam scoot1900, Commented Mar 8, 2018 at 6:01
Then you should either prevent duplicate entries in $array1 , $array2 while assigning or use array_unique to $finalarray — Jigar Shah
– Jigar Shah, Commented Mar 8, 2018 at 6:03

Gufran Hasan · Accepted Answer · 2018-03-08 06:00:01Z

1

You can use in_array() function as both arrays are index array.

$finalarray = array();
for ($i = 0; $i < count($arr1); $i++){
if(count(array_intersect($array1,$array2)) <= 1){// is the count of id is 1 or less save that whole row in the $finalarray
      $finalarray = $arr1[$i]; // saving the unique row.
}
else{
    continue;
}
}

make change in code:

$finalarray = array();
for ($i = 0; $i < count($arr1); $i++){
if(!in_array($array1[$i], $array2)){
      $finalarray[] = $array1[$i]; // saving the unique row.
}

}

edited Mar 8, 2018 at 6:00

answered Mar 8, 2018 at 5:33

Gufran Hasan

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8 Comments

Jigar Shah Over a year ago

should be : $finalarray[] = $array1[$i]; and also no need of continue

sam scoot1900 Over a year ago

@Gufran Hasan I am getting a syntax error in if statement?

Gufran Hasan Over a year ago

I have updated my amswer please check it again hope it will for wrok as you are looking

sam scoot1900 Over a year ago

@GufranHasan I don't know why but still is throwing me an error of unique value exist and then stops inserting?

sam scoot1900 Over a year ago

@GufranHasan ERROR: Unique violation: 7 ERROR: duplicate key value violates unique constraint

|

Bhaskar Jain · Accepted Answer · 2018-03-08 05:59:26Z

1

You can simply use array_intersect() to get common values between two array. for difference, can use array_diff()

$array1 = [1,2,3,4,5,6,7];
$array2 = [2,4,6];
//array_intersect — Computes the intersection of arrays
$result = array_intersect($array1, $array2);
print_r($result);
//array_diff — Computes the difference of arrays
$result = array_diff($array1, $array2);
print_r($result);

DEMO

answered Mar 8, 2018 at 5:59

Bhaskar Jain

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Comments

Jigar Shah · Accepted Answer · 2018-03-08 06:14:44Z

1

Rather than using 3 different arrays to get unique ids, you can do it by using one array. Make changes to your code as below:

$finalarray = array();

$arr1 = $msql->fetchAll(PDO::FETCH_ASSOC);
foreach($arr1 as $x){
    if (!in_array($x['id'],$finalarray)) { // check id is already stored or not       
        $finalarray[] = $x['id'];
    }
}


$arr2 = $psql->fetechAll(PDO::FETCH_ASSOC);
foreach($arr2 as $y){  
    if (!in_array($y['id'],$finalarray)) { // check id is already stored or not       
        $finalarray[] = $y['id'];
    }
}

answered Mar 8, 2018 at 6:14

Jigar Shah

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Comments

Vincent · Accepted Answer · 2018-03-08 05:41:34Z

0

Maybe you should make sure which array is larger before your loop ;

Or using array_diff:

$finalarray = array_diff($array1 , $array2) ?? [];
$finalarray = array_merge( array_diff($array2 , $array1) ?? [], $finalarray );

edited Mar 8, 2018 at 5:41

answered Mar 8, 2018 at 5:39

Vincent

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1 Comment

sam scoot1900 Over a year ago

My array1() will always be larger then array2()

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