PHP combine two number arrays into one array - php

I need a new array combining 2 array with calculation
$array1 = array(2,5,7,1);
$array2 = array(1,3,2,5);
result array should out put
$array3 = array(3,8,9,6);
is this possible in php i know array_merge function combine two array but how combine after calculation
NOTE :
this is possible in C# but i want to know can i do it php as well

If they are guaranteed to be matched in size then you can use something like this
$array3 = array();
for($x =0; $x<count($array1); $x++){
$array3[] = $array1[$x] + $array2[$x];
}
If the arrays are not guaranteed to be of the same size you can do the following
$array3 = array();
$max = max(count($array1), count($array2));
for($x =0; $x<$max; $x++){
$array3[] = (isset($array1[$x])?$array1[$x]:0)) + (isset($array2[$x])?$array2[$x]:0));
}
With the adoption of PHP 7 and it's null coalesce operator this code becomes much more readable:
$array3 = array();
$max = max(count($array1), count($array2));
for($x =0; $x<$max; $x++){
$array3[] = ($array1[$x] ?? 0) + ($array2[$x] ?? 0);
}

For this you have to use foreach loop
<?php
$array1 = array(2,5,7,1);
$array2 = array(1,3,2,5);
$array3= array();
foreach($array1 as $key=>$value)
{
$array3[$key] = $array1[$key]+$array2[$key];
}
print_r($array3)
?>

Related

PHP array comparision error

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 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.
}
}
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
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'];
}
}
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 );

Array conversion

Array conversion
$array1 = array(1,2,3,4,5,6,7,8,9,10);
in formate like
$arry2 = array([1],[2,3],[4,5,6],[7,8,9,10]);
use array_splice to consequently get items from array as arrays of increasing length
$i = 1;
$arry2 = [];
while ($t = array_splice($array1, 0, $i++))
$arry2[] = $t;

PHP put several arrays in one separated by ","

I have some arrays extracted from a XML-file. These are in
$array0 = (.......)
$array1 = (.......)
...
$arrayN = (.......)
Now I need a single array with all arrays in it separated by "," as
$masterArray = array($array0,
$array1,
...
$arrayN)
I tried
for ( $i = 0; $i < N; $i++) {
$masterArray = $masterArray + $array[$i];
}
with no result. I tried array_merge but this will give one
$masterArray(......................all items of all $arrays.....)
How can I do it right?
for ( $i = 0; $i < N; $i++) {
$temp = "array".$i;
$masterArray[$i] = ${$temp};
}
Given your exact definition of what you got and what you want the routine should be:
for ( $i = 0; $i < N; $i++) $masterArray[] = ${'array'.$i};
Not much to explain here. You make a new entry in an array with $variable[] = <entry>; and you access your numbered array with a variable variable, see:
http://php.net/manual/en/language.variables.variable.php
I guess you wont to create a multi dimension array:
$masterArray = array();
$masterArray[] = $array0;
$masterArray[] = $array1;
...
$masterArray[] = $arrayN;
this will in all arrays as element of the MasterArray:
$masterArray[0=>(....),1=>(....), ...];
Then access it like this:
$arr1_key1 = $masterArray[1]['key1'] ; //$array1['key1'];
You can add specific keys if you wont:
$masterArray['arr1'] = $array1;
$arr1_key1 = $masterArray['arr1']['key1'] ; //$array1['key1']
In general read some more to get better understanding on how to work with arrays ;)

Given an array of integers, what's the most efficient way to get the number of other integers in the array within n?

Given the following array:
$arr = array(0,0,1,2,2,5,6,7,7,9,10,10);
And assuming $n = 2, what is the most efficient way to get a count of each value in the array within $n of each value?
For example, 6 has 3 other values within $n: 5,7,7.
Ultimately I'd like a corresponding array with simply the counts within $n, like so:
// 0,0,1,2,2,5,6,7,7,9,10,10 // $arr, so you can see it lined up
$count_arr = array(4,4,4,4,4,3,3,4,4,4, 2, 2);
Is a simple foreach loop the way to go? CodePad Link
$arr = array(0,0,1,2,2,5,6,7,7,9,10,10);
$n = 2;
$count_arr = array();
foreach ($arr as $v) {
$range = range(($v-$n),($v+$n)); // simple range between lower and upper bound
$count = count(array_intersect($arr,$range)); // count intersect array
$count_arr[] = $count-1; // subtract 1 so you don't count itself
}
print_r($arr);
print_r($count_arr);
My last answer was written without fully groking the problem...
Try sorting the array, before processing it, and leverage that when you run through it. This has a better runtime complexity.
$arr = array(0,0,1,2,2,5,6,7,7,9,10,10);
asort($arr);
$n = 2;
$cnt = count($arr);
$counts = array_pad(array(), $cnt, 0);
for ($x=0; $x<$cnt; $x++) {
$low = $x - 1;
$lower_range_bound = $arr[$x]-$n;
while($low >= 0 && ($arr[$low] >= $lower_range_bound)) {
$counts[$x]++;
$low--;
}
$high = $x + 1;
$upper_range_bound = $arr[$x]+$n;
while($high < $cnt && $arr[$high] <= $upper_range_bound) {
$counts[$x]++;
$high++;
}
}
print_r($arr);
print_r($counts);
Play with it here: http://codepad.org/JXlZNCxW

PHP-ILooping an arrays values through a larger array

I want to know if it is possible to take an array and insert the array's values into a bigger array, multiple times, so that the values of the smaller array fill up the bigger array.
Say array1 has values ([0 => 'a'],[1 => 'b'],[2 => 'c']), and array2 can hold 8 values. So, how would I take the values of array1 and insert them into array2 continuously until array2 runs out of space, so that array2 would have the values 'a','b','c','a','b','c','a','b'?
Thanks in advance,
~Hussain~
Essentially, you want to loop over and over the small array, adding each element to the new array until it has reached the desired size.
Consider this:
$max = 8;
$Orig_Array = array('a', 'b', 'c');
$Next_Array = array();
while True
{
foreach($Orig_Array as $v)
{
$Next_Array[] = $v;
if(count($Next_Array) >= $max)
break 2;
}
}
Assuming that your input array is indexed sequentially:
$len = count($input);
$output = array();
for ($i = 0; $i < MAX_SIZE; ++$i)
$output[] = $input[$i % $len];
$a = array('a','b','c');
$desired = 8;
$b = array();
for($i=0;$i<($desired/count($a))+1;++$i) $b = array_merge($b,$a);
array_splice($b,$desired);
Or
$a = array('a','b','c');
$desired = 8;
$b = array();
for($i=0;$i<$desired/count($a);++$i) $b = array_merge($b,$a);
for($i=0;$i<($desired-count($b)-1);++$i) $b[] = $a[$i];
The first one fills up an array so that it has at least desired number of elements and cuts off the rest. The second one fills up an array up the desired number of elements modulo original array size and adds up the rest.
Here's one using the input array's internal pointer, to keep things conceptually simple:
$input = array(1, 2, 3);
$size = 32;
$output = array();
for ( $i = 0; $i < $size; $i++ ) {
$curr = current($input);
if ( $curr === false ) {
reset($input);
$curr = current($input);
}
$output[] = $curr;
next($input);
}
print_r($output);die;

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