PHP字符串辅助函数

string.php

<?php
/**
 * 表示Yes的字符串
 */
function is_yes ($word)
{
    $yes_words = array(
        '1','y','t','ok','yes','true','allow','agree'
    );
    return $word && in_array(strtolower($word), $yes_words);
}

/**
 * 保留字符串中的数字
 */
function get_numbers ($word)
{
    $times = preg_match_all('/[\d.]+/', $word, $matches);
    if ($times === 0 || $times === false) {
        return false;
    }
    return intval(implode(current($matches)));
}

/**
 * 产生16进制随机字符串
 */
function randHash ($length = 6)
{
    $length = $length > 32 ? 32 : $length;
    $hash = md5(mt_rand() . time());
    $buffers = substr($hash, 0, $length);
    return $buffers;
}

/**
 * 产生可识别的随机字符串
 */
function randString ($length = 8, $shuffles = 2, $good_letters = '')
{
    if (empty($good_letters)) {
        // 字符池，去掉了难以分辨的0,1,o,O,l,I
        $good_letters = 'abcdefghijkmnpqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ23456789';
    }
    srand((float) microtime() * 1000000);
    $buffer = '';
    // 每次可以产生的字符串最大长度
    $gen_length = ceil($length / $shuffles);
    while ($length > 0) {
        $good_letters = str_shuffle($good_letters);
        $buffer .= substr($good_letters, 0, $gen_length);
        $length -= $gen_length;
        $gen_length = min($length, $gen_length);
    }
    return $buffer;
}