Comparing PHP variable to values in text file

Question

I'm trying to validate that a php variable value exists in a text file then echo that value. Using the code below, my if statement is only true if the value in the variable is equal to the last value in the text file. If the value in the variable is equal to the first, second, third, etc values the if statement is false.

Here is my code:

$lines = file("file.txt");
$value = $_GET['value'];

    foreach ($lines as $line) {
        if (strpos($line, $value) !== false) {
            $output = $line;
        } else {
            $output = "Sorry, we don't recognize the value that you entered";
        }
    }

You overwrite $output variable every time. What do you expect? — u_mulder
– u_mulder, Commented Mar 2, 2016 at 20:22

AbraCadaver · Accepted Answer · 2016-03-02 20:37:32Z

1

The other answer corrects your code, however to match 1 or more with less code:

$output = preg_grep('/'.preg_quote($value, '/').'/', $lines);

To use the existing approach for only 1 match then break out of the loop and/or define the "Sorry..." output before:

$output = "Sorry, we don't recognize the value that you entered";

foreach ($lines as $line) {
    if (strpos($line, $value) !== false) {
        $output = $line;
        break;
    }
}

answered Mar 2, 2016 at 20:37

AbraCadaver

79.2k7 gold badges75 silver badges91 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

brandozz Over a year ago

could I also use in_array? if (in_array($value, $lines))

AbraCadaver Over a year ago

Only if the line and the value are identical. Meaning test will not match test line etc...

Xorifelse · Accepted Answer · 2016-03-02 20:27:52Z

1

As stated in the comment, you overwrite the variable with every loop with either line data or an error message.

   foreach ($lines as $line) {
        if (strpos($line, $value) !== false) {
            $output[] = $line;
        }
    }

    if(empty($output)){
      echo "Sorry, we don't recognize the value that you entered";
    } else {
      print_r($output);
    }

answered Mar 2, 2016 at 20:27

Xorifelse

7,9411 gold badge29 silver badges38 bronze badges

Collectives™ on Stack Overflow

Comparing PHP variable to values in text file

2 Answers 2

2 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

2 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related