I want to know if there is a map function or similar to use with array values? Say I have the following array..
$nums = array(1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
I want to multiply these values by 5, changing the array values where my expected output would be.
Array
(
[0] => 5
[1] => 10
[2] => 15
...... and so on
)
Is there a function i can use to do this?
Yes, and it is called array_map:
$nums = array_map(function($number) { return $number * 5; }, $nums);
Or with array_walk:
array_walk($nums, function(&$number) { $number *= 5; });
You can easily iterate over the array.
foreach ($nums as &$value) {
$value *= 5;
}
A little more complicated, you can use array_map() as well.
array_map(function($x) { return $x * 5; }, $nums);
There is no specific map function, but you can create your own using array_map or a foreach loop.
function map($n) {
return $n*5;
}
$nums = array(1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
print_r(array_map(map, $nums));
Or
function map($n, $array) {
foreach ($array as &$val) {
$val *= $n;
}
return $array;
}
$nums = array(1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
print_r(map(5, $nums));
Output
Array
(
[0] => 5
[1] => 10
[2] => 15
[3] => 20
[4] => 25
[5] => 30
[6] => 35
[7] => 40
[8] => 45
[9] => 50
)
Related
This question already has answers here:
Push elements from one array into rows of another array (one element per row)
(4 answers)
Closed 5 months ago.
I need to evenly/synchronously push values from my second array into the rows of my first array.
The arrays which have the same size, but with different keys and depths. The first is an array of rows and the second is a flat array.
$array1 = [
12 => [130, 28, 1],
19 => [52, 2, 3],
34 => [85, 10, 5]
]
$array2 = [4, 38, 33]
Preferred result:
[
12 => [130, 28, 1, 4],
19 => [52, 2, 3, 38],
34 => [85, 10, 5, 33]
]
(I would like to keep the same indices of array 1, however it is not mandatory.)
I have tried these methods, but none of them work because the first array keys are unpredictable.
$final = [];
foreach ($array1 as $idx => $val) {
$final = [$val, $array2[$idx]];
}
Another:
foreach ($array1 as $index => $subArray) {
$array1 [$index][] = $array2[$index];
}
Here is one way to do this:
$merged = array_map('array_merge', $array1, array_chunk($array2, 1));
$result = array_combine(array_keys($array1), $merged);
The second step with array_combine is necessary to reapply the non-sequential keys because array_map won't preserve them in the first step.
An example using foreach
<?php
$a = [
2 => [130, 28, 1, 1, 6],
3 => [52, 2, 3, 3, 27]
];
$b = [5, 38];
$output = [];
$idx = 0;
foreach ($a as $key => $value) {
$value[] = $b[$idx];
$output[$key] = $value;
++$idx;
}
print_r($output);
Sandbox HERE
You can loop $array1 using a foreach to get the current key $index
Get the value from $array2 by using a counter as the array key which, is incremented by 1 for every iteration.
Then add the value to the end of the current array.
$array1 = [
2 => [130, 28, 1, 1, 6],
3 => [52, 2, 3, 3, 27],
13 => [41, 20, 27, 13, 37]
];
$array2 = [89, 99, 109];
$counter = 0;
foreach ($array1 as $index => $subArray) {
$array1[$index][] = $array2[$counter++];
}
print_r($array1);
Output
Array
(
[2] => Array
(
[0] => 130
[1] => 28
[2] => 1
[3] => 1
[4] => 6
[5] => 89
)
[3] => Array
(
[0] => 52
[1] => 2
[2] => 3
[3] => 3
[4] => 27
[5] => 99
)
[13] => Array
(
[0] => 41
[1] => 20
[2] => 27
[3] => 13
[4] => 37
[5] => 109
)
)
See a PHP demo.
Maintaining a counter while iterating is a simple way of accessing second array values while iterating the first. It is not necessary to make multiple passes of the arrays, just one iteration is all that is required.
Codes: (Demos)
a mapper:
$i = -1;
var_export(
array_map(fn($row) => array_merge($row, [$array2[++$i]]), $array1)
);
a looper:
$i = -1;
foreach ($array1 as &$row) {
array_push($row, $array2[++$i]);
}
var_export($array1);
a walker:
$i = -1;
array_walk($array1, fn(&$row, $k) => array_push($row, $array2[++$i]));
var_export($array1);
If you don't care about preserving the first array's keys in the result array, then you can simply use:
var_export(
array_map('array_merge', $array1, array_chunk($array2, 1))
);
I have a multidimensional array. I need to check if any value in this array has contain same value. If, then execute. What is the better way to check this, or the simplest way TIA
$array[] = array(5, 10, 15, 20, 25, 30);
$array[] = array(1, 2, 3, 4, 5, 6);
$array[] = array(2, 6, 8, 10, 12, 14);
Array
(
[0] => Array
(
[0] => 5
[1] => 10
[2] => 15
[3] => 20
[4] => 25
[5] => 30
)
[1] => Array
(
[0] => 1
[1] => 2
[2] => 3
[3] => 4
[4] => 5
[5] => 6
)
[2] => Array
(
[0] => 2
[1] => 6
[2] => 8
[3] => 10
[4] => 12
[5] => 14
)
)
If I understood your question correctly, you are looking for a way of finding values that appears in more than one of the inner arrays..? Here are two solutions for that, using some built-in PHP array methods.
Setup
Flatten $array (initial step for both methods) using array_merge on itself
Code:
$array[] = array(5, 10, 15, 20, 25, 30);
$array[] = array(1, 2, 3, 4, 5, 6);
$array[] = array(2, 6, 8, 10, 12, 14, 5);
// 5, 10, 15, 20, 25, 30, 1, 2, 3, 4, 5, 6, 2, 6, 8, 10, 12, 14, 5
$array = call_user_func_array('array_merge', $array);
Method A
Get an array of unique values in $array (duplicates removed)
Get what was removed (= the duplicates) by comparing that array to the original $array
Make sure values appear only once in the final array
Code:
$duplicates =
array_unique(
array_diff_key(
$array,
array_unique($array)
)
);
// $duplicates = 5, 2, 6, 10
Method B
Get a list of how many times each value appears in $array
Filter that list keeping only values that appears more than once (= duplicates)
Get the keys of that list (the actual $array values)
Code:
$duplicates =
array_keys(
array_filter(
array_count_values($array),
function ($count) {
return $count > 1;
}
)
);
// $duplicates = 5, 10, 2, 6
Just loop through the array and subarray filling $isRepeated with values and frequencies of appearance. When $isRepeated[certain_value] exists means this value was found before:
$array[] = array(5, 10, 15, 20, 25, 30);
$array[] = array(1, 2, 3, 4, 5, 6);
$array[] = array(2, 6, 8, 10, 12, 14);
$isRepeated = array();
foreach($array as $subArray) {
foreach($subArray as $item) {
if (!isset($isRepeated[$item])) {
$isRepeated[$item] = 0;
} else {
$isRepeated[$item]++;
echo "\n<br>Item $item is repeated";
}
}
}
http://ideone.com/9yObII
Output:
Item 5 is repeated
Item 2 is repeated
Item 6 is repeated
Item 10 is repeated
This question already has answers here:
How to Sum Columns of a Multi-Dimensional Array?
(4 answers)
Closed 5 months ago.
I have an arrays with dynamic name. My array could be more than 3, depends and array variable should be unique
$loopThrice = 3;
$getSum = 0;
$total = array();
$array0 = array(5, 10, 15, 20, 25, 30);
$array1 = array(1, 2, 3, 4, 5, 6);
$array2 = array(2, 6, 8, 10, 12, 14);
for($a=0; $a < $loopThrice; $a++){ // loop 3x to get unique array name
foreach (${'array'.$a} as $key => $value) { // $array0, $array1, $array2,
//Right here is my problem, I'm not sure if this the correct way to get the sum of $array0,1,2
//get the sum of array0,1,2 -- newarray(8, 18, 26, 34, 42, 50)
$getSum +=
//store newarray
array_push($total, $getSum);
}
}
I need to get an output like this:
Array (
[0] => 8
[1] => 18
[2] => 26
[3] => 34
[4] => 43
[5] => 50
)
Why aren't you using a multidimensional array?
$array = array(); // hungarian notation
$array[] = array(5, 10, 15, 20, 25, 30);
$array[] = array(1, 2, 3, 4, 5, 6);
$array[] = array(2, 6, 8, 10, 12, 14);
In this case you will have an array of arrays:
Array
(
[0] => Array
(
[0] => 5
[1] => 10
[2] => 15
[3] => 20
[4] => 25
[5] => 30
)
[1] => Array
(
[0] => 1
[1] => 2
[2] => 3
[3] => 4
[4] => 5
[5] => 6
)
[2] => Array
(
[0] => 2
[1] => 6
[2] => 8
[3] => 10
[4] => 12
[5] => 14
)
)
You can go with nested for loops:
$sumArray = array();
$arrayCount = count($array);
$elementCount = 0;
foreach($array as $subarray)
{
$count = count($subarray);
$elementCount = $elementCount < $count ? $count : $elementCount;
}
for($i = 0; $i < $elementCount; $i++)
{
$sumArray[$i] = 0;
for($j = 0; $j < $arrayCount; $j++)
{
$sumArray[$i] += $array[$j][$i];
}
}
print_r($sumArray);
The output is
Array
(
[0] => 8
[1] => 18
[2] => 26
[3] => 34
[4] => 42
[5] => 50
)
Now, if you have a disproportioned sub-arrays (i.e. different count of elements in each sub-array), you will still get some sort of result, as missing elements will be assumed to be 0. So, with the input of:
$array = array(); // hungarian notation
$array[] = array(5, 10, 15, 20, 25);
$array[] = array(1, 2, 3, 4, 5, 6);
$array[] = array(2, 6, 8, 10);
You will still get the result:
Array
(
[0] => 8
[1] => 18
[2] => 26
[3] => 34
[4] => 30
[5] => 6
)
Well the multi array is the way to go, but you can still do it this way:
$loopThrice = 3;
$getSum = 0;
$total = array();
$array0 = array(5, 10, 15, 20, 25, 30);
$array1 = array(1, 2, 3, 4, 5, 6);
$array2 = array(2, 6, 8, 10, 12, 14);
// find which arrray has the most values
for($a=0; $a < $loopThrice; $a++){
$max_index = (count(${'array'.$a}) > $max_index ? count(${'array'.$a}) : $max_index);
}
for($i=0; $i < $max_index; $i++){
for($a=0; $a < $loopThrice; $a++){
$total[$i] += ${'array'.$a}[$i];
}
}
print_r($total);
// prints Array ( [0] => 8 [1] => 18 [2] => 26 [3] => 34 [4] => 42 [5] => 50 )
This should work for you:
$array0 = array(5, 10, 15, 20, 25, 30);
$array1 = array(1, 2, 3, 4, 5, 6);
$array2 = array(2, 6, 8, 10, 12, 14);
$var_prefix = 'array';
$arr_count = 0;
$max_fields = 0;
while(isset(${$var_prefix.$arr_count})) {
$data[] = ${$var_prefix.$arr_count};
if(count(${$var_prefix.$arr_count})>$max_fields) {
$max_fields = count(${$var_prefix.$arr_count});
};
$arr_count++;
}
for($i=0; $i<$max_fields; $i++) {
$result[$i] = array_sum(array_column($data, $i));
}
echo '<pre>';
print_r($result);
echo '</pre>';
die();
I don't know why you have individual array variables, but the process remains the same as if you declare a single array containing those arrays as rows in a multi-dimensional array.
Once you have a multi-dimensional array, the spread operator (...) will feed columns of data into array_map()'s custom function body -- where array_sum() can be called upon.
This task is effectively summing transposed data.
Code: (Demo)
var_export(
array_map(fn() => array_sum(func_get_args()), $array0, $array1, $array2)
);
Or:
var_export(
array_map(fn(...$cols) => array_sum($cols), $array0, $array1, $array2)
);
Output (from either approach):
array (
0 => 8,
1 => 18,
2 => 26,
3 => 34,
4 => 42,
5 => 50,
)
I have an array of some values which I need to convert to new array and sum every value with all previous values. For example (array length, keys and values always differ), this is what I have:
Array
(
[0] => 1
[1] => 1
[2] => 5
[3] => 1
[4] => 1
[7] => 1
[8] => 3
[9] => 1
)
and this is what I need:
Array
(
[0] => 1
[1] => 2
[2] => 7
[3] => 8
[4] => 9
[7] => 10
[8] => 13
[9] => 14
)
I tried many different ways but always stuck at something or realized that I'm wrong somewhere. I have a feeling that I'm trying to reinvent a wheel here, because I think there have to be some simple function for this, but had no luck with finding solution. This is last way I tried:
$array = array( "0"=> 1, "1"=> 1, "2"=> 5, "3"=> 1, "4"=> 1, "7"=> 1, "8"=> 3, "9"=> 1 );
$this = current($array);
$next = next($array);
$end = next(end($array));
$sum = 0;
$newArray = array();
foreach ($array as $val){
if($val != $end){
$sum = ($this += $next);
array_push($newArray, $sum);
}
}
print_r($newArray);
..unfortunately wrong again. I spend lot of time finding ways how not to get where I need to be, can someone kick me into right direction, please?
Suggest you to use array_slice() & array_sum()
$array = array( "0"=>1,"1"=>1,"2"=>5,"3"=>1,"4"=>1,"7"=>1,"8"=>3,"9"=>1);
$keys = array_keys($array);
$array = array_values($array);
$newArr = array();
foreach ($array as $key=>$val) {
$newArr[] = array_sum(array_slice($array, 0, $key+1));
}
$newArr = array_combine($keys, $newArr);
print '<pre>';
print_r($newArr);
print '</pre>';
Output:
Array
(
[0] => 1
[1] => 2
[2] => 7
[3] => 8
[4] => 9
[7] => 10
[8] => 13
[9] => 14
)
Reference:
array_slice()
array_sum()
array_combine()
array_keys()
let assume your array variable is $a;
You can use simple for loop
for($i=1;$i<sizeof($a);$i++)
{
$a[$i]=$a[$i]+$a[$i-1];
}
You can just go over the array sum and add to a new array (in a simple way):
$array = array( "0"=> 1, "1"=> 1, "2"=> 5, "3"=> 1, "4"=> 1, "7"=> 1, "8"=> 3, "9"=> 1 );
var_dump($array);
$newArray = array();
$sum = 0;
foreach ($array as $a){
$sum += $a;
$newArray[]=$sum;
}
var_dump($newArray);
$sums = array_reduce($array, function (array $sums, $num) {
return array_merge($sums, [end($sums) + $num]);
}, []);
In other words, this iterates over the array (array_reduce) and in each iteration appends (array_merge) a number to a new array ($sums) which is the sum of the previous item in the array (end($sums)) and the current number. Uses PHP 5.4+ array syntax ([]).
You complicated too much. Loop trough all elements of array and add current element to sum. Then assign that sum to new array.
$array = array( "0"=> 1, "1"=> 1, "2"=> 5, "3"=> 1, "4"=> 1, "7"=> 1, "8"=> 3, "9"=> 1 );
$sum = 0;
$newArray = array();
foreach ($array as $key=>$val){
$sum += $val;
$newArray[$key]=$sum;
}
Make sure to get indexes right.
I have 3 arrays:
array(1, 5, 1);
array(3, 2, 7, 5 ,4);
array(4, 3, 6, 5)
I want to merge them and get such result:
array(
array(1, 3, 4),
array(5, 2, 3),
array(1, 7, 6),
array(5, 5),
array(4)
);
What is the easiest way?
$arrs = array(
array(1, 5, 1),
array(3, 2, 7, 5, 4),
array(4, 3, 6, 5),
);
$result = array();
$num_arrs = count($arrs);
for($i = 0; $i < $num_arrs; $i++){
$size = count($arrs[$i]);
for($j = 0; $j < $size; $j++){
if(!isset($result[$j]))
$result[$j] = array();
$result[$j][] = $arrs[$i][$j];
}
}
Demo
Assuming you have the latest version of PHP (5.5), you can use this:
$input = array(
array(1,5,1),
array(3,2,7,5,4),
array(4,3,6,5)
);
$output = array_column($input,null);
If you don't have the latest version, see the original PHP version for a shim.
Alternatively, for this specific case (ie. a specialised shim), try this:
$input = array(...); // see code block above
$output = array();
foreach($input as $arr) foreach($arr as $i=>$v) $output[$i][] = $v;
$arrays = array(
array(1, 5, 1),
array(3, 2, 7, 5 ,4),
array(4, 3, 6, 5)
);
$combined = array();
foreach($arrays as $array) {
foreach($array as $index => $val) {
if(!isset($combined[$index])) $combined[$index] = array();
$combined[$index][] = $val;
} }
After that $combined holds what you want.
Is this what you want?
You can use array_map
<?php
$a = array( 1, 5, 1 );
$b = array( 3, 2, 7, 5 ,4 );
$c = array( 4, 3, 6, 5 );
$d = array_map( function() {
return array_filter( func_get_args() );
}, $a, $b, $c );
print_r( $d );
?>
Output
Array
(
[0] => Array
(
[0] => 1
[1] => 3
[2] => 4
)
[1] => Array
(
[0] => 5
[1] => 2
[2] => 3
)
[2] => Array
(
[0] => 1
[1] => 7
[2] => 6
)
[3] => Array
(
[1] => 5
[2] => 5
)
[4] => Array
(
[1] => 4
)
)