如何使用PHP将原始文本文件数据转换为JSON？

Question

I was given a task to sort out data from a text file into JSON using PHP and object oriented principal. The text file has information and is displayed as follows (ignore #):

#product_num:name:cost
5:tv:59.99
7:radio:10.99

I created a class and in this class I have one function that ignores any # or blank spaces from the data and puts the data in an array and json_encode it. When I echo this data it looks like this:

[{"1":"5:tv:59.99","2":"7:radio:10.99"}]

Is it possible to write other functions to separate the data further, for example so it looks more like:

[{"product_number":"5","name":"tv","cost":"59.99"},{"product_number":"7","name":"radio","cost":"10.99"}]

If so can anyone give me any pointers and tips because I have no idea where or how to begin even after numerous google searches.

Answer 1

Your file format is basically a csv file and PHP has a CSV import function. http://php.net/manual/en/function.fgetcsv.php

If you scroll down and check the CsvImporter example, you can copy/paste that and add a json_encode:

$importer = new CsvImporter("small.txt",true,":"); 
$data = $importer->get(); 
echo json_encode($data); 

[{
    "\ufeff#product_num": "5",
    "name": "tv",
    "cost": "59.99"
},
{
    "\ufeff#product_num": "7",
    "name": "radio",
    "cost": "10.99"
}]

Answer 2

There is a function inside PHP for reading value separated lines, like CSV; it's called fgetcsv which can also be used in object oriented PHP through SplFileObject::fgetcsv .

You will need to read each line, add the variable labels then append that to an array.

Depending on the size of the file you may need to optimize for memory usage as your array grows by saving as you proceed through the file.

<?php
$file = new SplFileObject('test.txt', 'r'); //Load the file
$file->current(); //Skip the first line (Side note: seek(1) did not appear to work while testing)

$result = [];
do { //While there are lines in the file
    list($product_num, $name, $cost) = $file->fgetcsv(':'); //Break the line on the : delimiter into an array and populate the array into the three named values
    $result[] = [ //Build the new json representation and add to result array
        'product_num' => $product_num,
        'name' => $name,
        'cost' => $cost,
    ];
} while (!$file->eof());

file_put_contents('output.json', json_encode($result)); //Save the result