String Replace in PHP

I have string named File_Test_name_1285931677.xml. File is the common word and 1285931677 开发者_如何学运维is a random number. I want to remove File_ and _1285931677.xml, i.e. prefix up to first _ and suffix from last _ on.

You can do this with explode, array_slice and implode:

implode('_', array_slice(explode('_', $str), 1, -1))

With explode the string gets cut into parts at _ so that the result is an array like this:

array('File', 'Test', 'name', '1285931677.xml')

With array_slice everything from the second to the second last is grabbed, e.g.:

array('Test', 'name')

This is then put back together using implode, resulting in:

Test_name

Another approach would be to use strrpos and substr:

substr($str, 5, strrpos($str, '_')-5)

Since File_ has fixed length, we can use 5 as the starting position. strrpos($str, '_') returns the position of the last occurrence of _. When subtracting 5 from that position, we get the distance from the fifth character to the position of the last occurrence that we use as the length of the substring.

I would be lazy and use:

$file_name = "File_Test_name_1285931677.xml";
preg_replace("/^File_Test_name_\d+\.xml$/", "Test_name.xml", $filename);

This is provided you always want to call it Test_name. If Test_name changes:

preg_replace("/^File_(.+)_\d+\.xml$/", "$1.xml", $file_name);

EDIT (Again): Reread your update. You'll want the second example.

If you only want to replace as string replace_string is the way to go

$str = "File_Test_name_1285931677.xml";
echo str_replace("File_Test_name_1285931677.xml",'Test_name', $str);

If you want to rename a file you need to use rename:

rename("/directors_of_file/File_Test_name_1285931677.xml", "Test_name");

$filename = preg_replace('/^File_(.*?)_\d+\.xml$/', '$1', $filename);

You could also use substr but clearly a str_replace with pattern matching would be better:

$file = "File_test_name_12345.xml";
$new_file = substr($file,strpos($file,'_')+1,strrpos($file,'_')-strpos($file,'_')).substr($file,strrpos($file,'.'));