How to restrict duplicate data entry to an existing data in a text file in PHP?

Question

I am having a 'names.txt' text file having names like John, Mike, Julia. Now i enter another set of names in append mode to the existing 'names.txt' file like Steve, Ben, Mike. How can I restrict the 'Mike' duplicate entry in php? Or how can I prompt an error message something like 'Mike, name already existed. Please enter another name' so that duplication can be avoided.

The code is

<!DOCTYPE html>
<html>
<head>
<title>Form Page</title>    
</head>
<body>

<form action="Files.php" method="POST">
<textarea rows="15" cols="30" value="textbox" name="textbox"></textarea></br>
<input type="submit" value="Save" name="Save">
<input type="submit" value="Fetch" name="Fetch">
</form>

</body>
</html>

<?php

/*** Get names from 'names.txt' file and prints the names stored in it ***/
if(isset($_POST['Fetch'])){
    $file_names = "names.txt";
    $current_names = file_get_contents($file_names);
    echo nl2br($current_names); 
}

/*** Get names from text box and Put to the 'names.txt' file in append mode ***/
if(isset($_POST['Save'])){

    $current_names = $_POST["textbox"];
    file_put_contents("names.txt", PHP_EOL.$current_names, FILE_APPEND);

    /*** Get names form 'names.txt' file and prints the names stored in it ***/
    $file_names = "names.txt";
    $current_names = file_get_contents($file_names);
    echo nl2br($current_names);
}

?>

post your code to help.

Lucas Henrique
– Lucas Henrique

2014-04-27 17:40:09 +00:00
Commented Apr 27, 2014 at 17:40 — Lucas Henrique
– Lucas Henrique, Commented Apr 27, 2014 at 17:40
Hi Lucas Henrique, I've posted the code. Please check it.

Latchu
– Latchu

2014-04-27 17:48:57 +00:00
Commented Apr 27, 2014 at 17:48 — Latchu
– Latchu, Commented Apr 27, 2014 at 17:48
@Latchu I've posted a new solution, try it out.

Pedro Lobito
– Pedro Lobito

2014-04-27 18:33:34 +00:00
Commented Apr 27, 2014 at 18:33 — Pedro Lobito
– Pedro Lobito, Commented Apr 27, 2014 at 18:33

low_rents · Accepted Answer · 2014-04-27 18:28:44Z

5

when separating your text-file entries with PHP_EOL: (be careful - the output of PHP_EOL depends on the operating system PHP is running on!)

//new name to insert if not in file:
$new_name = "Martin";

$file_content = file_get_contents('names.txt');

//names into array elements
$content_array = explode(PHP_EOL, $file_content);

//trim spaces and stuff from the data in your array:
foreach($content_array AS $key => $value)
{
    $content_array[$key] = trim($value);
}


if(in_array($new_name, $content_array)) echo "name found - don't save it again";

edited Apr 27, 2014 at 18:28

answered Apr 27, 2014 at 17:53

low_rents

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2 Comments

low_rents Over a year ago

just replace the delimiter in the explode() - function with the one you use. seems like you are using "PHP_EOL" -> explode(PHP_EOL, $file_content);

low_rents Over a year ago

changed my answer now to fit to your updated question. and be careful - "PHP_EOL" is depending on the operating system your php-code is running on.

Deano · Accepted Answer · 2014-04-27 17:46:00Z

2

probably the best way would be to

read the text file line by line and load them into an array
loop through the array comparing each value against the newly given value (the new name) - this can be done using in_array()
add if false or echo error out if true.

answered Apr 27, 2014 at 17:46

Deano

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Comments

Pankaj Garg · Accepted Answer · 2014-04-27 18:18:56Z

<!DOCTYPE html>
<html>
<head>
<title>Form Page</title>
</head>
<body>

<form action="Files.php" method="POST">
<textarea rows="15" cols="30" value="textbox" name="textbox"></textarea></br>
<input type="submit" value="Save" name="Save">
<input type="submit" value="Fetch" name="Fetch">
</form>

</body>
</html>

<?php

/*** Get names from 'names.txt' file and prints the names stored in it ***/
if(isset($_POST['Fetch'])){
    $file_names = "names.txt";
    $current_names = file_get_contents($file_names);
    echo nl2br($current_names);
}

$currentNamesContainer = explode(PHP_EOL, $current_names);

/*** Get names from text box and Put to the 'names.txt' file in append mode ***/
if(isset($_POST['Save'])){

    $newName = $_POST["textbox"]; // changed variable name to NewName

    // If new name does not exist in current container, then just append it...otherwise bail!
    if (!in_array($newName, $currentNamesContainer)) {
        file_put_contents("names.txt", PHP_EOL.$newName, FILE_APPEND);
    }

    /*** Get names form 'names.txt' file and prints the names stored in it ***/
    $file_names = "names.txt";
    $current_names = file_get_contents($file_names);
    echo nl2br($current_names);
}

?>

Algorithm : $existingData = file_get_contents('names.txt');

// Now parse this string and store names in an array (list of names), that depends on your format of file...

$yourNewName = 'Mike';

// Now check is this exists in your current array.

if (in_array($yourNewName, $currentArray)) {
   // exit with error
}

// Insert new name .

//This is pseudo code i have written. If you post your code, i can try more help.

Pedro Lobito · Accepted Answer · 2014-04-27 18:34:08Z

Try this:

/* names.txt 
mike
peter
louis
hamilton
*/


<!DOCTYPE html>
<html>
<head>
<title>Form Page</title>    
</head>
<body>

<form action="Files.php" method="POST">
<textarea rows="15" cols="30" value="textbox" name="textbox"></textarea></br>
<input type="submit" value="Save" name="Save">
<input type="submit" value="Fetch" name="Fetch">
</form>

</body>
</html>

<?php

/*** Get names from 'names.txt' file and prints the names stored in it ***/
if(isset($_POST['Fetch'])){
    $file_names = "names.txt";
    $current_names = file_get_contents($file_names);
    echo nl2br($current_names); 
}

/*** Get names from text box and Put to the 'names.txt' file in append mode ***/
if(isset($_POST['Save']) && !empty($_POST['textbox'])){

    $file_names = "names.txt";
    $current_names_onfile = file_get_contents($file_names);
    $current_names = $_POST["textbox"];
    $arr = explode("\r", $current_names);
    foreach($arr as $name)
    {
        #remove line breaks
        $name = preg_replace('/[\r\n]/m', '', $name);
        #if the name doesn't exist on file stores it.
       if (!preg_match("/^\b$name\b\$/m", $current_names_onfile)) {
       file_put_contents("names.txt", PHP_EOL.$name, FILE_APPEND);
       }else{
           echo "$name already exists<br />";
       }
    }
    /*** Get names form 'names.txt' file and prints the names stored in it ***/
    $file_names = "names.txt";
    $current_names = file_get_contents($file_names);
    echo nl2br($current_names);

   }else if(isset($_POST['Save'])){
    echo "please type something";
}

?>

Funk Forty Niner · Accepted Answer · 2014-04-27 19:55:10Z

2

So simple..

$data   = file('names.txt', FILE_IGNORE_NEW_LINES);
$search = 'Jakarta';

echo (in_array($search, $data)) ? "Already exists" : "Available";

edited Apr 27, 2014 at 19:55

Funk Forty Niner

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answered Apr 27, 2014 at 18:52

W Kristianto

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