PHP 字串的大、小寫轉換

我們常常會想要將英文字串全部轉成大寫或小寫，今天就是要來介紹這該如何達成!

首先就來看看將字串轉成大寫:

1. <?php
2. 
   
3. $str = "Mary Had A Little Lamb."; 
4. 
   
5. $str = strtoupper($str); 
6. 
   
7. echo $str;  //  result: MARY HAD A LITTLE LAMB.
8. 
   
9. ?>

再來看將字串轉成小寫:

1. <?php
2. 
   
3. $str = "Mary Had A Little Lamb."; 
4. 
   
5. $str = strtolower($str); 
6. 
   
7. echo $str;  //  result: mary had a little lamb.
8. 
   
9. ?>

是不是很簡單呢~?