php cookbook String.

README.php

//截取字符串
$substring = substr($string,$start,$length);

//使用给定字符串替换
$new_string = substr_replace($old_string,$new_substring,$start);

//反转字符串
string strrev (string $string)

//反转字符串(单词)
$new_string = implode(' ', array_reverse(explode(' ', $string)));

//子字符串替换
mixed str_replace ( mixed $search , mixed $replace , mixed $subject [, int &$count ] )

//大小写转换
ucwords()
ucfirst()
strtolower()
strtoupper()

// 去空格(字符穿)
trim()
ltrim()
rtrim()

//去掉数组元素空格
function trim_value(&$value)
{
    $value = trim($value);
}

$fruit = ['apple', 'banana ', ' watermelon'];
var_dump($fruit);

array_walk($fruit, 'trim_value');
var_dump($fruit);

//csv文件读写
fputcsv()
fgetcsv()

//格式化输出
$books = array( array('Elmer Gantry', 'Sinclair Lewis', 1927),
                array('The Scarlatti Inheritance','Robert Ludlum', 1971),
                array('The Parsifal Mosaic','William Styron', 1979) );

foreach ($books as $book) {
    print pack('A26A15A4', $book[0], $book[1], $book[2]) . "\n";
}
//也可以使用 str_pad() 来代替
$title = str_pad(substr($book[0], 0, 26), 26, ' ');
$author = str_pad(substr($book[1], 0, 15), 15, ' ');
$year = str_pad(substr($book[2], 0, 4), 4, ' ');

//将字符串转化为数组
str_split()

//分割字符串为数组
array explode ( string $delimiter , string $string [, int $limit ] )
array preg_split ( string $pattern , string $subject [, int $limit = -1 [, int $flags = 0 ]] )

打断字符串为指定数量的字串
string wordwrap ( string $str [, int $width = 75 [, string $break = "\n" [, bool $cut = false ]]] )