PHP: how to remove the last line break from the text file? - php

Question

In a school work, I built a site for a fictional space museum in my city using PHP. It has a Data Inclusion and Data Consultation systems, but I have a problem with the consultation that I want to know how to solve: how to delete the last line break from the file?
Data Inclusion
In the restricted area of the site, I have a HTML5 form with 5 fields (name, addres, telephone number, sex and visited exhibitions) that sends the data by the method POST to a function in PHP that writes it on a given txt file by using the fwrite command:
fwrite ($pointer, "$name | $addres | $telephone | $sex | $exhibitions " .PHP_EOL);
As you can see, it writes in a txt file the data entered on the form, plus a line break. The pointer is the variable used by fopen to open the file that I need to work. Example of output:
Márcio Aguiar | Belmiro Braga Street | 1234-5678 | M | Planets of Solar System
Joana Tobias | Santos Dummont Avenue | 8765-4321 | F | Black Holes, Satellites
Data Consultation
Then there is a consultation system. It has a loop that runs until the file ends. Inside this loop there is a variable named $buffer that gets one line of the txt file each time. It is then exploded to create a array named $lines[$counter]. To print it nicely, I use a array_combine where I join the names of the fields on another array ($keys) to the values written in $lines[$counter], and attibutes that to $combined[$counter]. Then the loop ends and I use a print_r inside <pre></pre> to see the data written in $combined, while mantaining the spaces and breaks that HTML would otherwise ignore. Here is the code:
$keys = array ("Name", "Address", "Telephone", "Sex", "Visited exhibition");
for ($counter=0;!feof($reader);$counter++){
$buffer = fgets($reader);
$lines[$counter] = explode(" | ", $buffer);
$combined[$counter] = array_combine($keys, $lines[$counter]);
}
echo "<pre>";
print_r($combined);
echo "</pre>";
Example of output:
Array
(
[0] => Array
(
[Name] => Márcio Aguiar
[Address] => Belmiro Braga Street
[Telephone] => 1234-5678
[Sex] => M
[Visited exhibitions] => Planets of Solar System
)
[1] => Array
(
[Name] => Joana Tobias
[Address] => Santos Dummont Avenue
[Telephone] => 8765-4321
[Sex] => F
[Visited exhibitions] => Black Holes, Satellites
)
[2] =>
)
Here you can see that a 2 Array was created blank. It's caused by the last line, that contains only a line break inserted by the form above. I need to remove this last line break, and only that one, but don't know how. I want to know! Not knowing causes the exhibition of an error when the execution arrive at the array_combine, because it's needed that the two arrays have the same number of elements, and 2 is blank. Here the error:
Warning: array_combine(): Both parameters should have an equal number of elements in E:\Aluno\Documents\Wamp\www\trab_1\area_restrita\consulta.php on line 60

Answer 1

Original answer:
To remove a trailing line break from any text, you can use trim(), however in your case, you just need to use fopen in append mode:
$handle = fopen("/path/to/file", "a");
Then get rid of the PHP_EOL:
fwrite ($pointer, "$name | $addres | $telephone | $sex | $exhibitions");
Edit: You're right that appending doesn't append to a new line. I was mistaken. So you could use trim() like I mentioned earlier. I created a quick example using file_get_contents() and file_put_contents() and it appears to do what you want:
<?php
$file = 'test.txt';
// Set existing contents (for testing sake)
$orig_contents = "bob | 123 fake street | 1234567890 | yes, please | no\n";
$orig_contents .= "bob | 123 fake street | 1234567890 | yes, please | no\n";
$orig_contents .= "bob | 123 fake street | 1234567890 | yes, please | no\n";
$orig_contents .= "bob | 123 fake street | 1234567890 | yes, please | no\n";
file_put_contents($file, $orig_contents);
// Here is how you could add a single new line with append mode
// Notice the trailing \n
file_put_contents($file, "billy | 456 fake street | 2345678901 | no | yes\n", FILE_APPEND);
// Get contents from the file and remove any trailing line breaks
$contents = trim(file_get_contents($file));
$keys = array ("Name", "Address", "Telephone", "Sex", "Visited exhibition");
// Explode based on the new line character
$lines = explode("\n", $contents);
foreach ($lines as $line) {
$values = explode(" | ", $line);
$combined[] = array_combine($keys, $values);
}
print_r($combined);
This prints:
Array
(
[0] => Array
(
[Name] => bob
[Address] => 123 fake street
[Telephone] => 1234567890
[Sex] => yes, please
[Visited exhibition] => no
)
[1] => Array
(
[Name] => bob
[Address] => 123 fake street
[Telephone] => 1234567890
[Sex] => yes, please
[Visited exhibition] => no
)
[2] => Array
(
[Name] => bob
[Address] => 123 fake street
[Telephone] => 1234567890
[Sex] => yes, please
[Visited exhibition] => no
)
[3] => Array
(
[Name] => bob
[Address] => 123 fake street
[Telephone] => 1234567890
[Sex] => yes, please
[Visited exhibition] => no
)
[4] => Array
(
[Name] => billy
[Address] => 456 fake street
[Telephone] => 2345678901
[Sex] => no
[Visited exhibition] => yes
)
)

Answer 2

The problem is with the way you're reading the file. You're testing for EOF before reading from the file. But feof() won't be true until you try to read while you're at the end of the file.
Instead, you should test whether fgets() returns a line.
for ($counter = 0; $buffer = fgets($reader); $counter++) {
$lines[$counter] = explode(" | ", $buffer);
$combined[$counter] = array_combine($keys, $lines[$counter]);
}
DEMO
To explain further, suppose you have a file with one line in it. When $counter is 0, you call feof(), and it returns false. So you then read the first line, and add it to $lines and $combined. Then you increment $counter and go back to the beginning of the loop.
When $counter is 1, you call feof(). It's still not true, because you haven't tried to read at the end of the file yet. Then you try to read the next line, but there is no line there, fgets returns false and you assign this to $buffer. This is treated as an empty string by explode(), so you add an empty array to $lines and $combined. Then you increment $counter and go back to the beginning of the loop.
Then you call feof(), and this time it returns true because you tried to read at the end of the file on the previous iteration. So the loop ends.
As you can see from the above, even though the file only has 1 line, you end up with 2 entries in your arrays, because you didn't test for EOF until after you read too far.

Answer 3

In case you want to get rid of the last line break in data you pulled from the db ($res) you can use the following snippet
for ($i=0; $i <count($res); $i++) {
// If this is not last item then add items separated by line break
if($i+1 < count($res)) {
file_put_contents("file.txt", $res[$i].PHP_EOL, FILE_APPEND);
}
// If this is the last item, then don't append the final line break
else {
file_put_contents("file.txt", $res[$i], FILE_APPEND);
}
}