如何在PHP中修剪字符串中的n个字符？

Question

Checking for the best way to trim a string. How to trim n characters from a string in PHP?

May be I need the first n characters, sometimes I need the a th character to z th character, otherwise the last n characters. Which is the best(hope the fastest) way to trim a string to a specific number of characters?

Actually, looking for some combinations of PHP string functions.

Working with regular expressions doesn't felt much comfortable.

UPDATE:

For eg. from a string like "The quick brown fox jumps over the lazy dog.", take:

1. The first n=>5 characters: "The q"
2. Substring from a=>5th character to z=>12th character: "quick br"
3. The last n=>5 characters: " dog."

Answer 1

First $n characters:

substr($text, 0, $n);

Substring from $a=>5th character to $z=>12th character: "quick br"

substr($text, $a, ($z-$a));

Last n characters:

substr($text, -$n);

http://php.net/substr