Obtain first line of a string in PHP - php

Question

In PHP 5.3 there is a nice function that seems to do what I want:
strstr(input,"\n",true)
Unfortunately, the server runs PHP 5.2.17 and the optional third parameter of strstr is not available. Is there a way to achieve this in previous versions in one line?

Answer 1

For the relatively short texts, where lines could be delimited by either one ("\n") or two ("\r\n") characters, the one-liner could be like
$line = preg_split('#\r?\n#', $input, 2)[0];
for any sequence before the first line feed, even if it an empty string,
or
$line = preg_split('#\r?\n#', ltrim($input), 2)[0];
for the first non-empty string.
However, for the large texts it could cause memory issues, so in this case strtok mentioned below or a substr-based solution featured in the other answers should be preferred.
When this answer was first written, almost a decade ago, it featured a few subtle nuances
it was too localized, following the Opening Post with the assumption that the line delimiter is always a single "\n" character, which is not always the case. Using PHP_EOL is not the solution as we can be dealing with outside data, not affected by the local system settings
it was assumed that we need the first non-empty string
there was no way to use either explode() or preg_split() in one line, hence a trick with strtok() was proposed. However, shortly after, thanks to the Uniform Variable Syntax, proposed by Nikita Popov, it become possible to use one of these functions in a neat one-liner
but as this question gained some popularity, it's better to cover all the possible edge cases in the answer. But for the historical reasons here is the original solution:
$str = strtok($input, "\n");
that will return the first non-empty line from the text in the unix format.
However, given that the line delimiters could be different and the behavior of strtok() is not that straight, as "Delimiter characters at the start or end of the string are ignored", as it says the man page for the original strtok() function in C, now I would advise to use this function with caution.

Answer 2

It's late but you could use explode.
<?php
$lines=explode("\n", $string);
echo $lines['0'];
?>

Answer 3

$first_line = substr($fulltext, 0, strpos($fulltext, "\n"));
or something thereabouts would do the trick. Ugly, but workable.

Answer 4

try
substr( input, 0, strpos( input, "\n" ) )

Answer 5

echo str_replace(strstr($input, '\n'),'',$input);

Answer 6

list($line_1, $remaining) = explode("\n", $input, 2);
Makes it easy to get the top line and the content left behind if you wanted to repeat the operation. Otherwise use substr as suggested.

Answer 7

not dependent from type of linebreak symbol.
(($pos=strpos($text,"\n"))!==false) || ($pos=strpos($text,"\r"));
$firstline = substr($text,0,(int)$pos);
$firstline now contain first line from text or empty string, if no break symbols found (or break symbol is a first symbol in text).

Answer 8

try this:
substr($text, 0, strpos($text, chr(10)))

Answer 9

You can use strpos combined with substr. First you find the position where the character is located and then you return that part of the string.
$pos = strpos(input, "\n");
if ($pos !== false) {
echo substr($input, 0, $pos);
} else {
echo 'String not found';
}
Is this what you want ?
l.e.
Didn't notice the one line restriction, so this is not applicable the way it is. You can combine the two functions in just one line as others suggested or you can create a custom function that will be called in one line of code, as wanted. Your choice.

Answer 10

Many times string manipulation will face vars that start with a blank line, so don't forget to evaluate if you really want consider white lines at first and end of string, or trim it. Also, to avoid OS mistakes, use PHP_EOL used to find the newline character in a cross-platform-compatible way (When do I use the PHP constant "PHP_EOL"?).
$lines = explode(PHP_EOL, trim($string));
echo $lines[0];

Answer 11

A quick way to get first n lines of a string, as a string, while keeping the line breaks.
Example 6 first lines of $multilinetxt
echo join("\n",array_splice(explode("\n", $multilinetxt),0,6));
Can be quickly adapted to catch a particular block of text, example from line 10 to 13:
echo join("\n",array_splice(explode("\n", $multilinetxt),9,12));