"DIRECTORY_SEPARATOR is not necessarily needed, PHP always converts / to the appropriate character in its file functions.It is good practice, though.", but you may always use DIRECTORY_SEPARATOR if you only display it on the screen
下列常量由此扩展定义，且仅在此扩展编译入 PHP 或在运行时动态载入时可用。
Note:
PATH_SEPARATOR是在 PHP 4.3.0-RC2 中引入。
"DIRECTORY_SEPARATOR is not necessarily needed, PHP always converts / to the appropriate character in its file functions.It is good practice, though.", but you may always use DIRECTORY_SEPARATOR if you only display it on the screen
While debugging, this function return error number and it's difficult to remember all errors codes, so I think it's should be there.
<?php
print_r([
'PREG_NO_ERROR' => PREG_NO_ERROR,
'PREG_INTERNAL_ERROR' => PREG_INTERNAL_ERROR,
'PREG_BACKTRACK_LIMIT_ERROR' => PREG_BACKTRACK_LIMIT_ERROR,
'PREG_RECURSION_LIMIT_ERROR' => PREG_RECURSION_LIMIT_ERROR,
'PREG_BAD_UTF8_ERROR' => PREG_BAD_UTF8_ERROR,
'PREG_BAD_UTF8_OFFSET_ERROR' => PREG_BAD_UTF8_OFFSET_ERROR,
]);
?>
Result:
Array
(
[PREG_NO_ERROR] => 0
[PREG_INTERNAL_ERROR] => 1
[PREG_BACKTRACK_LIMIT_ERROR] => 2
[PREG_RECURSION_LIMIT_ERROR] => 3
[PREG_BAD_UTF8_ERROR] => 4
[PREG_BAD_UTF8_OFFSET_ERROR] => 5
)
In PHP 5.6 you can make a variadic function.
<?php
/**
* Builds a file path with the appropriate directory separator.
* @param string $segments,... unlimited number of path segments
* @return string Path
*/
function file_build_path(...$segments) {
return join(DIRECTORY_SEPARATOR, $segments);
}
file_build_path("home", "alice", "Documents", "example.txt");
?>
In earlier PHP versions you can use func_get_args.
<?php
function file_build_path() {
return join(DIRECTORY_SEPARATOR, func_get_args($segments));
}
file_build_path("home", "alice", "Documents", "example.txt");
?>
For my part I'll continue to use this constant because it seems more future safe and flexible, even if Windows installations currently convert the paths magically. Not that syntax aesthetics matter but I think it can be made to look attractive:
<?php
$path = join(DIRECTORY_SEPARATOR, array('root', 'lib', 'file.php');
?>
DIRECTORY_SEPARATOR is not necessarily needed, PHP always converts / to the appropriate character in its file functions.
It is good practice, though.