PHP - How to import data from a *.csv file and display the required cell value given a condition

Question

I am trying to display on an Wordpress webpage certain values contained in a CSV file (which is hosted online) by using PHP. I update this CSV file every X hours via a Python FTP code.

The webpage has the following permalink https://example.com/user/id/. The CSV file is hosted on the website and is made up by multiple rows with the same number of columns. Example:

username,user_id,value1,value2,value3,value4
mario,1,1000,1100,1200,1300
luigi,2,2000,2100,2200,2300
...

I would like to parse the CSV file and display values selectively depending on the id of the user.

I can get the id of the user from the permalink of the page with the following function:

<?php

$permalink = get_permalink();  // $permalink is now 'https://example.com/user/1/'

$permalink = trim($permalink, "/"); // $permalink is now 'https://example.com/user/1'

$user_id = substr($permalink, strrpos($permalink, '/') + 1); // $user_id is now '1'

?>

Now that I have the user_id, I would like to show the values in its row. For example, if user_id is "1" (second column of the CSV file), then I would like to display on the webpage the following output:

Value 1 is 1000
Value 2 is 1100
Value 3 is 1200
Value 4 is 1400

To display the values in the webpage I tried to use something like this:

$csv_url = "https://example.com/path/filename.csv"
$f = file_get_contents($csv_url);
$items = explode(',', $f);
foreach($items as $item){
    $user = explode(",", $item);
    // $user[0] - will contain the first number
    // $user[1] - will contain second
    // $user[3] - will contain third
}

But this is not working as intended because it cannot separate the rows.

What PHP code would achieve the result I would like to get?

EDIT New code is:

<?php
$permalink = 'https://example.com/user/1/';  // $permalink is now 'https://example.com/user/1/'

$permalink = trim($permalink, "/"); // $permalink is now 'https://example.com/user/1'

$user_id = substr($permalink, strrpos($permalink, '/') + 1); // $user_id is now '1'

$csv_url = "https://example.com/path/users.csv"
$f = file_get_contents($csv_url);
$lines = explode("\n", $f);
foreach($lines as $line){
    $user = explode(",", $line);

    if ($user[1] !== $user_id) {
        continue;
    }

echo "<strong>Points:</strong>"
echo "Value 1: " . $user[2]
echo "Value 2" . $user[3]
echo "Value 3: " . $user[4]
echo "Value 4: " . $user[5]
echo "Value 5: " . $user[6]

}
?>

Answer 1

Try exploding by the newline character first, and afterwars the , sign. Like this:

$csv_url = "https://example.com/path/filename.csv"
$f = file_get_contents($csv_url);
$lines = explode("\n", $f);
foreach($lines as $line){
    $user = explode(",", $line);


    // $user[0] - will contain the username
   // $user[1] - will contant id
}

Answer 2

why not just use the csv parser built into php then you can use a proper array or object to do this easily?

if (($handle = fopen("test.csv", "r")) !== false) {
    while (($data = fgetcsv($handle, 1000, ",")) !== false) {
        for ($c = 0; $c < count($data); $c++) {

        }
    }
}

Answer 3

Thanks @Tim - Yes I did steal part of your answer, but I am lazy like that.

I just wanted to add this too it.

 if (false !== ($handle = fopen("test.csv", "r"))) { //constants go on the left, which prevents accidental assignment `if(false = $foo)` throws an error, the other way sets foo to false. 
    //I do declare!! 
    $headers = false;
    $num_headers = 0;

    while (($data = fgetcsv($handle, 1000, ",")) !== false) {

        //get headers from the first row
       if(!$headers){
           $headers = array_unique($data);
           $num_headers = count($headers);
           continue; //skip to next row - just because depending how you handle "below" you may need it.
       }else if( count($data) != $num_headers){
           //rows here have missing or extra delimiters or duplicated header names
           //you should ignore, throw an error or try to fix them etc. depending on your needs.
       }else{
           //combine headers and data
           $row = array_combine($headers, $data);
           //now you can use associative keys
           echo $row['username'];
           echo $row['user_id'];
           //... etc
       }
    }
}

Above I am showing how you can combine a header row with a data row, to allow use of the headers as keys in the data array. This prevents positional errors that can happen if the order of the CSV changes (and it's just easier to read and use ) etc...

array_combine will bomb out if the two arrays are different length, this can happen because of errors in the CSV file such as an extra or missing delimiter. We need to catch (or test for this case) and act accordingly. It can and does happen for various reasons that the file will have some error like this in it, best to not be surprised by it.

All your headers are uniquely named so I didn't worry about it too much but remember when using them as array keys, the keys must be unique therefor so must your headers.

Hope it helps!

Answer 4

I managed to get it working with this code:

<?php
$permalink = get_permalink();  // $permalink is now 'https://example.com/user/1/'

$permalink = trim($permalink, "/"); // $permalink is now 'https://example.com/user/1'

$user_id = substr($permalink, strrpos($permalink, '/') + 1); // $user_id is now '1'

$csv_url = "https://example.com/path/users.csv";
$f = file_get_contents($csv_url);
$lines = explode("\n", $f);

foreach($lines as $line){
    $user = explode(",", $line);

    if ($user[0] == $user_id) {
        break;
    }

}
echo "<strong>Points:</strong> <br>";
echo "Value 1: " . $user[2] . "<br>";
echo "Value 2: " . $user[3] . "<br>";
echo "Value 3: " . $user[4] . "<br>";
echo "Value 4: " . $user[5] . "<br>";
echo "Value 5: " . $user[6] . "<br>";
?>

Answer 5

Yes, you should use csv-purposed php functions on csv files.

No, you don't need to use yoda-speak in conditions with appropriately written parentheses.

No, you don't have to declare the delimiter parameter in fgetcsv() because comma is the default. If you want to set the length parameter, there is some performance benefit stated in the documentation page.

Yes, you should most definitely break the loop immediately after finding your match so that you don't kill efficiency.

Yes, you should extract/consume the header before looping to avoid unnecessary conditionals and temporary variables.

Untested snippet:

if (($handle = fopen("test.csv", "r")) !== false) {
    $header = array_slice(fgetcsv($handle, 1000), 2);
    while (($row = fgetcsv($handle, 1000)) !== false) {
        if ($row[1] == $id) {
            foreach (array_slice($row, 2) as $index => $value) {
                echo ucfirst(preg_replace('~\D+\K~', ' ', $header[$index])) , ' is ' , $value;
                break;
            }
        }
    }
    fclose($handle);
}