When Do I Use the PHP Constant "PHP_Eol"

When do I use the PHP constant PHP_EOL?

Yes, PHP_EOL is ostensibly used to find the newline character in a cross-platform-compatible way, so it handles DOS/Unix issues.

Note that PHP_EOL represents the endline character for the current system. For instance, it will not find a Windows endline when executed on a unix-like system.

\n vs. PHP_EOL vs. br?

DOS, Unix, and Mac (pre-OS X and OS X) all use different characters or character combinations to represent "go to the next line."

DOS - Uses a CR+LF (that's ASCII 13 followed by an ASCII 10, or \r\n) to represent a new line.
Unix - Uses an LF (that's ASCII 10, or \n) to represent a new line.
Mac (pre-OS X) - Uses a CR (that's ASCII 13, or \r) to represent a new line.
Mac (OS X) - Like Unix, uses an LF to represent a new line.

Therefore, when to use each one depends on what you're going for. If you're writing for a specific platform without the intention of portability, use the character or character combination to break lines that matter to that platform. The purpose of PHP_EOL is to automatically choose the correct character for the platform, so that your new lines are platform-independent.

All of these appear as a single space within a browser as browsers collapse whitespace into a display space for display purposes (unless you're using <pre> as you mentioned, or CSS that changes the behavior of whitespace). This is where <br> comes in, as you've mentioned, which will convert these \n new line characters into <br> so that they provide line breaks in HTML display.

constant like PHP_EOL for tabulation php

Ok I found solution

chr(9) wrote tabulation to output file

Thanks!

When do I use PHP_EOL instead of \n and vice-versa ? Ajax/Jquery client problem

The constant PHP_EOL should generally be used for platform-specific output.

Mostly for file output really.
Actually the file functions already transform \n ←→ \r\n on Windows systems unless used in fopen(…, "wb") binary mode.

For file input you should prefer \n however. While most network protocols (HTTP) are supposed to use \r\n, that's not guaranteed.

Therefore it's best to break up on \n and remove any optional \r manually:
```
$lines = array_map("rtrim", explode("\n", $content));
```
Or use the file(…, FILE_IGNORE_NEW_LINES) function right away, to leave EOL handling to PHP or auto_detect_line_endings.
A more robust and terser alternative is using preg_split() and a regexp:
```
$lines = preg_split("/\R/", $content);
```
The \R placeholder detects any combination of \r + \n. So would be safest, and even work for Classic MacOS ≤ 9 text files (rarely seen in practice).
^{Obligatory microoptimization note:

While regex has a cost, it's surprisingly often speedier than manual loops and string postprocessing in PHP.}

And there are a few classic examples where you should avoid PHP_EOL due to its platform-ambiguity:

Manual generation of network protocol payloads, such as HTTP over fsockopen().
For mail() and MIME construction (which really, you shouldn't do tediously yourself anyway).
File output, if you want to consistently write just Unix \n newlines regardless of environment.

So use a literal "\r\n" combination when not writing to files, but preparing data for a specific context that expects network linebreaks.

Why PHP_EOL is equal to 0?

What is the good way to remove every PHP_EOL without cutting off 0 ?

$value = rtrim($value, PHP_EOL);

See http://php.net/rtrim.

As for why PHP_EOL equals 0, see PHP type juggling, "String" == 0 and "String" == true.

What is the benefit of \n and PHP_EOL in PHP?

A web browser interprets the output of a PHP program as HTML, so \n and \r\n will not appear to do anything, just like inserting a newline in an HTML file. On the other hand, <br /> makes a new line in the interpreted HTML (hence "line BReak"). Therefore, <br /> will make new lines, whereas \r\n will not do anything.

Which is the correct way of using core predefined constant PHP_EOL inside a double quoted string and single quoted string?

echo "$people->john drank some $juices[0] juice.".PHP_EOL;

Here .(dot) works like it will first concatenate the total string then prints.

But comes to ,

echo "The character at index -2 is $string[-2].", PHP_EOL;

it won't concatenate. it will print one after other based on ,

PHP_EOL seems undefined

Use this:

$text = str_replace(array("\r\n", "\n\r", "\n", "\r"), ' ', $text)

This should cover all the cases regardless of where the system is hosted on.

You can rely on PHP_EOL if all the data is constructed in that OS that is manipulating it, otherwise it is best to use a specific newline character.

When Do I Use the PHP Constant "PHP_Eol"