exploding string with multiple delimiter

Question

i have a string like

$str = "1-a,2-b,3-c";

i want to convert it into a single array like this

$array = [
             1 => "a", 
             2 => "b", 
             3 => "c"
];

what i do is

$str = "1-a,2-b,3-c";
$array = [];
$strex = explode(",", $str);
foreach ($strex as $str2) {
    $alphanumeric = explode("-", $str2);
    $array[$alphanumeric[0]] = $alphanumeric[1];
}

can i do this in a better way?

Answer 1

You can use preg_match_all for this:

<?php
    $str = "1-a,2-b,3-c";

    preg_match_all('/[0-9]/', $str, $keys);
    preg_match_all('/[a-zA-Z]/', $str, $values);

    $new = array_combine($keys[0], $values[0]);

    echo '<pre>'. print_r($new, 1) .'</pre>';

here we take your string, explode() it and then preg_match_all the $value using patterns:

• /[0-9]/ -> numeric value
• /[a-zA-Z]/ -> letter

then use array_combine to get it into one array

Thanks to u_mulder, can shorten this further:

<?php
    $str = "1-a,2-b,3-c";

    preg_match_all('/(\d+)\-([a-z]+)/', $str, $matches);
    $new = array_combine($matches[1], $matches[2]);

    echo '<pre>'. print_r($new, 1) .'</pre>';

Answer 2

just a little benchmark:

• 5000 iterations
• Debian stretch, php 7.3
• parsed string: "1-a,2-b,3-c,4-d,5-e,6-f,7-g,8-h,9-i"

[edit] Updated with the last 2 proposals [/edit]

Answer 3

You can use preg_split with array_filter and array_combine,

function odd($var)
{
    // returns whether the input integer is odd
    return $var & 1;
}
function even($var)
{
    // returns whether the input integer is even
    return !($var & 1);
}
$str = "1-a,2-b,3-c";
$temp = preg_split("/(-|,)/", $str); // spliting with - and , as said multiple delim
$result =array_combine(array_filter($temp, "even", ARRAY_FILTER_USE_KEY), 
                       array_filter($temp, "odd",ARRAY_FILTER_USE_KEY));
print_r($result);

array_filter — Filters elements of an array using a callback function

Note:- ARRAY_FILTER_USE_KEY - pass key as the only argument to callback instead of the value

array_combine — Creates an array by using one array for keys and another for its values

Demo

Output:-

Array
(
    [1] => a
    [2] => b
    [3] => c
)

Answer 4

One way to do with array_map(),

<?php
$my_string = '1-a,2-b,3-c';
$my_array = array_map(function($val) {list($key,$value) = explode('-', $val); return [$key=>$value];}, explode(',', $my_string));
foreach(new RecursiveIteratorIterator(new RecursiveArrayIterator($my_array)) as $k=>$v){
    $result[$k]=$v;
}
print_r($result);
?>

WORKING DEMO: https://3v4l.org/aYmOH

Answer 5

Not a better way but one more example:

$str = "1-a,2-b,3-c";
$arr1 = explode(",", preg_replace("/\-([a-zA-Z]+)/", "", $str));
$arr2 = explode(",", preg_replace("/([0-9]+)\-/", "", $str));

print_r(array_combine($arr1, $arr2));

Answer 6

Tokens all the way down...

<?php

$str   = '1-a,2-b,3-c';
$token = '-,';

if($n = strtok($str, $token))
    $array[$n] = strtok($token);
while($n = strtok($token))
    $array[$n] = strtok($token);

var_export($array);

Output:

array (
    1 => 'a',
    2 => 'b',
    3 => 'c',
  )

Or perhaps more terse without the first if...:

$array = [];
while($n = $array ? strtok($token) : strtok($str, $token))
    $array[$n] = strtok($token);

Answer 7

Mandatory one-liner (your mileage may vary):

<?php
parse_str(str_replace([',', '-'], ['&', '='], '1-a,2-b,3-c'), $output);
var_export($output);

Output:

array (
    1 => 'a',
    2 => 'b',
    3 => 'c',
  )

Answer 8

This one explodes the string as the OP has on the comma, forming the pairs: (1-a) and (2-b) etc. and then explodes those pairs. Finally array_column is used to create the associated array:

<?php

$str = '1-a,2-b,3-c';
$output =
array_column(
    array_map(
        function($str) { return explode('-', $str); }, 
        explode(',', $str)
    ),
    1,
    0
);
var_export($output);

Output:

array (
  1 => 'a',
  2 => 'b',
  3 => 'c',
)

Answer 9

You can do one split on both the , and -, and then iterate through picking off every other pair ($k&1 is a check for an odd index):

<?php
$str = '1-a,2-b,3-c';

foreach(preg_split('/[,-]/', $str) as $k=>$v) {
    $k&1 && $output[$last] = $v;
    $last = $v;
}

var_export($output);

Output:

array (
  1 => 'a',
  2 => 'b',
  3 => 'c',
)

The preg_split array looks like this:

array (
  0 => '1',
  1 => 'a',
  2 => '2',
  3 => 'b',
  4 => '3',
  5 => 'c',
)