如何用php在txt文件中增加价值

Question

I want to add a value (not overwrite!) to a txt file with file_put_contents

This is what i have so far:

$fileUserId = fopen("fileUserId.txt", "w") or die("Unable to open file!");
$UserIdtxt = $UserID."||";
file_put_contents("fileUserId.txt", $UserIdtxt, FILE_APPEND);
fclose($fileUserId);

$UserID is an integer, like 1, 2, 3 etc.

So when the the UserID is 1, the fileUserId.txt looks like this:

1||

When there is another user with ID 2, the fileUserId.txt should look like this:

1||2||

But he overwrites the file so it becomes this:

2||

What i am doing wrong?

Answer 1

Remove the fopen and fclose line and you are fine. file_put_contents does this internally. And fopen("fileUserId.txt", "w") clears the file.

Note:

'w' Open for writing only; place the file pointer at the beginning of the file and truncate the file to zero length. If the file does not exist, attempt to create it.

Answer 2

You can as well do it differently. The commented code below illustrates how:

<?php

    $txtFile    = __DIR__ . "/fileUserId.txt";
    $UserID     = 9; //<== THIS VALUE IS FOR TESTING PURPOSES, 
                     //<== YOU SHOULD HAVE ACCESS TO THE ORIGINAL $UserID;

    //CHECK THAT THE FILE EXISTS AT ALL
    if( file_exists($txtFile) ){
        // GET THE CONTENTS OF THE FILE... & STORE IT AS A STRING IN A VARIABLE
        $fileData       = file_get_contents($txtFile);

        // SPLIT THE ENTRIES BY THE DELIMITER (||)
        $arrEntries     = preg_split("#\|\|#", $fileData);

        // ADD THE CURRENT $UserID TO THE $arrEntries ARRAY
        $arrEntries[]   = $UserID;

        // RE-CONVERT THE ARRAY TO A STRING...
        $strData        = implode("||", $arrEntries);

        // SAVE THE TEXT FILE BACK AGAIN...
        file_put_contents($txtFile, $strData);
    }else{
        // IF FILE DOES NOT EXIST ALREADY, SIMPLY CREATE IT
        // AND ADD THE CURRENT $UserID AS THE FIRST ENTRY...
        file_put_contents($txtFile, $UserID);
    }