PHP - Perform parsing rules on nested array - php

Question

So I have a nested array, that mimics a table layout (columns and rows):
{
"1": [
{
"row": "My name is Trevor\n"
},
{
"row": "Can you see me?\n"
},
{
"row": "\f"
}
],
"2": [
{
"row": Hey there! Some other text.\n"
},
{
"row": "What is up?\n"
},
{
"row": "\f"
}
],
"3": [
{
"row": "Some text on the third column. First row."
},
{
"row": "\f"
}
]
}
So "1", "2", "3" are the columns and then under each column, there can be any number of rows.
Now I am trying to do, so my users can perform various parsing rules on either:
All columns and all rows.
Specific columns and all rows.
Whenever a column / row has been parsed, it should be returned to the "original array".
For this, I have created a class that will apply the different parsing rules I have in specified. Getting the parsing rule works fine. I am currently stuck in the actual text transformation/parsing aspect.
Consider I have a parsing rule called "regexTextReplace", that looks like this:
class regexTextReplace
{
private $pattern;
private $replacement;
public function __construct(array $arguments)
{
$this->pattern = $arguments['pattern'];
$this->replacement = $arguments['replacement'];
}
public function apply(array $table, $column = false): array
{
$table = $column ? $table[$column] : $table;
return array_map('self::regex_replace', $table);
}
public function regex_replace(array $table)
{
return preg_replace($this->pattern, $this->replacement, $table);
}
}
This is how I'm using it:
$options = [
'pattern' => '/Trevor/i',
'replacement' => 'Oliver',
];
$engine = new regexTextReplace($options);
$columns = $engine->apply($document->content, 1); //"1" is the specific column.
$columns returns:
[
{
"row": "My name is Oliver\n"
},
{
"row": "Can you see my?\n"
},
{
"row": "\f"
}
]
Two problems here:
It successfully apply the parsing rule (Trever is replaced with Oliver). But it only returns the first column, but I want the entire original array to be transformed.
If I remove the 1 from the apply() method, I get below error:
Array to string conversion
on below line:
return preg_replace($this->pattern, $this->replacement, $table);
Can anyone guide me in the right direction, so I can perform my parsing rule on any column or on all columns, and return the transformed data back to my original array?

Answer 1

I would rewrite the apply function to loop over the entire table, processing each column if the column argument is not set, or if it matches the current table column:
public function apply(array $table, $column = false): array
{
$out = array();
foreach ($table as $col => $rows) {
if ($column === false || $col == $column) {
$out[$col] = array_map('self::regex_replace', $rows);
}
else {
$out[$col] = $rows;
}
}
return $out;
}
Demo on 3v4l.org

Answer 2

You could rewrite your apply method to this:
public function apply(array $table, $columns = false): array
{
$columns = $columns === false ? array_keys($table) : (array)$columns;
return array_map(function ($column) use ($table, $columns) {
return in_array($column, $columns) ? array_map('self::regex_replace', $table[$column]) : $table[$column];
}, array_keys($table));
}
You can pass either a single column, or an array of columns, or nothing (false) to specify the columns you want adjusted.
Demo: https://3v4l.org/Kn4FY

Answer 3

Just loop it and do the regex on all subarrays:
$content = json_decode($json, true);
$options = [
'pattern' => '/Trevor/i',
'replacement' => 'Oliver',
];
$engine = new regexTextReplace($options);
foreach($content as $key => $v){
$columns[$key] = $engine->apply($content, $key);
}
var_dump($columns);
Working demo:
https://3v4l.org/Pk2rC
The benefit of looping in the "PHP" side instead of in the class is that you can still apply the regex to only one or two of the subarrays.
If you loop in the class then you need to pass more arguments to restrict the looping or do some type of array slicing.