Fill in gaps in an array where a dash appears? [duplicate] - php

Question

This question already has answers here:
Populate array of integers from a comma-separated string of numbers and hyphenated number ranges
(8 answers)
Closed 6 months ago.
I have a text box that a user can paste a string of comma separated numbers and it puts that into an array. However, in some cases that string may contain numbers separated by a dash and I need to fill in the missing numbers where that dash appears.
Example:
1, 4, 7, 20-25, 31, 46, 100
Needs to become:
1, 4, 7, 20, 21, 22, 23, 24, 25, 31, 46, 100
How might I go about doing this? The gap wont always be 5 numbers and there could be more than one set of dashed numbers in the string that is input.

Answer 1

Here is one way, without a regex:
It is:
Parsing the input string with str_getcsv() to separate it into its individual elements, then trimming whitespace around each element with trim() and array_map().
Iterating over each element, searching for a dash. If it finds a dash, it found a range of numbers, so it separates them into the start and end indexes by explode()ing on the dash, and forms the correct range between $start and $end with range(). It then merges that newly formed range with what has already been formed as the result using array_merge().
If, during iteration, it didn't find a dash, it assumes you have a literal number, and adds just that number to the resulting array.
That's it!
$input = '1, 4, 7, 20-25, 31, 46, 100';
$entries = array_map( 'trim', str_getcsv( $input));
$result = array();
foreach( $entries as $entry) {
if( strpos( $entry, '-') !== false) {
list( $start, $end) = explode( '-', $entry);
$result = array_merge( $result, range( trim($start), trim($end)));
} else {
$result[] = $entry;
}
}
You can see from this demo that it produces:
Array (
[0] => 1
[1] => 4
[2] => 7
[3] => 20
[4] => 21
[5] => 22
[6] => 23
[7] => 24
[8] => 25
[9] => 31
[10] => 46
[11] => 100 )
Edit: To form the resulting string, instead of the array, you just need a call to implode(), like so:
echo implode( ', ', $result);
This will produce:
1, 4, 7, 20, 21, 22, 23, 24, 25, 31, 46, 100

Answer 2

$data = '1, 4, 7, 20-25, 31, 46, 100';
$elts = explode(',', $data);
$res = array();
foreach ($elts as $elt) {
$elt = trim($elt);
if (preg_match('/(\d+)-(\d+)/', $elt, $matches) === 1) {
$res = array_merge($res, range($matches[1], $matches[2]));
} else {
$res[] = intval($elt);
}
}
var_dump($res);

Answer 3

My solution :DEMO HERE
First delete spaces using str_replace()
explode() string using , to array of integers.
explode() every element using - to check if it's a range or just a single integer.
if it's a range , loop using for() or range() and add $i to $newArray , else add the element to $newArray.
implode() using , and print the result.
PHP code :
<?php
$str=str_replace(' ', '', '1, 4, 7, 20-25, 31, 46, 100');
$arr = explode(',',$str);
foreach($arr as $elem){
$values=explode('-',$elem);
if(count($values)!=1) for($i=$values[0];$i<=$values[1];$i++) $newArr[]=$i;
else $newArr[]=$elem;
}
echo implode(',',$newArr);
?>
OUTPUT:
1,4,7,20,21,22,23,24,25,31,46,100

Answer 4

Simple code :
split string by delimiter , with explode();
remove space from the beginning and end of a string with trim;
function array_map is used so you don't need to do foreach loop just to apply trim() to every element;
create empty array where you will store new elements;
iterate over each number or range with foreach;
do points 1., 2. and 3. again on every iteration;
split string by delimiter - with explode() even if string doesn't have delimiter - in it; result will be array with one or multi elements;
if point 6. has array with multiple elements, that means that there is range involved, so use function range() to create an array containing a range of elements;
store new numbers to point 4. array with array_merge() function;
when point 4. array is full generated; sort values with sort(), so you don't have output like 5, 3, 1, 4 etc. (delete this function if you don't need this functionality);
remove duplicates with array_unique(), so you don't have output like 4, 4, 4, 4, 5 etc. (delete this function if you don't need this functionality)
to convert array back to string like you inputed, use implode() function.
|
function fillGaps($s) {
$s = array_map('trim', explode(',', $s));
$ss = [];
foreach ($s as $n) {
$n = array_map('trim', explode('-', $n));
if (count($n) > 1) $n = range($n[0], end($n));
$ss = array_merge($ss, $n);
}
sort($ss); # remove if you don't need sorting
$ss = array_unique($ss); # remove if duplicates are allowed
return implode(', ', $ss);
}
Example :
Your example :
echo fillGaps('1, 4, 7, 20 - 25, 31, 46, 100');
# 1, 4, 7, 20, 21, 22, 23, 24, 25, 31, 46, 100
This code will also work for multiple gaps, like :
echo fillGaps('100-105-110');
# 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110
You can even go reverse :
echo fillGaps('10-5');
# 5, 6, 7, 8, 9, 10
# or remove function sort() and output will be 10, 9, 8, 7, 6, 5
Remove duplicates :
echo fillGaps('2-4, 4, 4, 5');
# 2, 3, 4, 5

Answer 5

This can be done without the using a regular expression.
Get the user input, explode with , as the delimiter, and you'll get an array of all numbers.
Now use an if statement to check if the string contains a dash.
If it does, explode it again with the delimiter -. Now you'll get two numbers
Use range() to create an array of numbers within that range
Use implode() to join them by a comma.
As a useful function:
Code:
function fill_string_gaps($input)
{
$parts = explode(',', $input);
$resultArray = array();
foreach ($parts as $part) {
if(strpos(trim($part), '-')) {
list($num1, $num2) = explode('-', $part);
$expanded_num_array = range($num1, $num2);
$resultArray = array_merge($resultArray, $expanded_num_array);
} else {
$resultArray[] = trim($part);
}
}
$comma_separated = implode(', ', $resultArray);
return $comma_separated;
}
Usage:
$input = '1, 4, 7, 20-25, 31, 46, 100';
echo fill_string_gaps($input;)
Test cases:
echo fill_string_gaps('1-5');
echo fill_string_gaps('1-5, 12, 24');
echo fill_string_gaps('2, 2, 4, 5-8');
Output:
1, 2, 3, 4, 5
1, 2, 3, 4, 5, 12, 24
2, 2, 4, 5, 6, 7, 8
See it in action!