因为我是一个音乐迷(但只是一个初级编码员)，所以我制作了这个脚本来随机选择一些音高(从MySQL表中)(以帮助非正式的串行风格构图)。它给出了9-12个不重复的音高名称，每组3-4个音高。例如:C、Eb、Gb (break) A、D、F、Db (break) Ab、G、b
1)是否有更有效的方法来达到预期的结果?代码看起来很麻烦。我只是让它通过一系列if-else语句。2)正如代码开头的注释所示，各种分布的概率是不等的。在实践中，这很好，但如果有其他选择就更好了。
谢谢。
<?php
/*
This code assigns pitch distributions to one of the following combinations.
The first number is possible values of $numtot:
9 = 3,3,3
10 = 4,3,3;
3,4,3; 3,3,4
11 = 4,4,3; 4,3,4;
3,4,4;
12 = 4,4,4;
3,3,3,3;
Note that probabilities are unequal:
eg: 3,3,3 is 2x as likely to occur as 3,3,3,3
*/
$sandbox = mysql_connect("localhost", "root", "password")
or die(mysql_error());
mysql_select_db("sandbox", $sandbox);
$numtot = rand(9,12);
$sql = "SELECT * FROM pitches ORDER BY RAND() LIMIT $numtot";
$result = mysql_query($sql, $sandbox);
echo "Your pitches are:<br>";
if ($numtot==9) {
while ($row = mysql_fetch_array ($result)) {
if ($numtot>7)
{echo $row['Pitch'].", ";}
else if ($numtot==7)
{echo $row['Pitch']."<br>";}
else if ($numtot>4)
{echo $row['Pitch'].", ";}
else if ($numtot==4)
{echo $row['Pitch']."<br> ";}
else if ($numtot>1)
{echo $row['Pitch'].", ";}
else
{echo $row['Pitch'];}
$numtot--;
}
}
else if ($numtot==10) {
$num1 = rand(3,4);
if ($num1 == 4){
while ($row = mysql_fetch_array ($result)) {
if ($numtot>7)
{echo $row['Pitch'].", ";}
else if ($numtot==7)
{echo $row['Pitch']."<br>";}
else if ($numtot>4)
{echo $row['Pitch'].", ";}
else if ($numtot==4)
{echo $row['Pitch']."<br> ";}
else if ($numtot>1)
{echo $row['Pitch'].", ";}
else
{echo $row['Pitch'];}
$numtot--;
}
}
else {
$num2 = rand(3,4);
if ($num2 == 4) {
while ($row = mysql_fetch_array ($result)) {
if ($numtot>8)
{echo $row['Pitch'].", ";}
else if ($numtot==8)
{echo $row['Pitch']."<br>";}
else if ($numtot>4)
{echo $row['Pitch'].", ";}
else if ($numtot==4)
{echo $row['Pitch']."<br> ";}
else if ($numtot>1)
{echo $row['Pitch'].", ";}
else
{echo $row['Pitch'];}
$numtot--;
}
}
else {
while ($row = mysql_fetch_array ($result)) {
if ($numtot>8)
{echo $row['Pitch'].", ";}
else if ($numtot==8)
{echo $row['Pitch']."<br>";}
else if ($numtot>5)
{echo $row['Pitch'].", ";}
else if ($numtot==5)
{echo $row['Pitch']."<br> ";}
else if ($numtot>1)
{echo $row['Pitch'].", ";}
else
{echo $row['Pitch'];}
$numtot--;
}
}
}
}
else if ($numtot==11) {
$num1 = rand(3,4);
if ($num1 == 4){
while ($row = mysql_fetch_array ($result)) {
if ($numtot>8)
{echo $row['Pitch'].", ";}
else if ($numtot==8)
{echo $row['Pitch']."<br>";}
else if ($numtot>4)
{echo $row['Pitch'].", ";}
else if ($numtot==4)
{echo $row['Pitch']."<br> ";}
else if ($numtot>1)
{echo $row['Pitch'].", ";}
else
{echo $row['Pitch'];}
$numtot--;
}
}
else {
$num2 = rand(3,4);
if ($num2 == 4) {
while ($row = mysql_fetch_array ($result)) {
if ($numtot>8)
{echo $row['Pitch'].", ";}
else if ($numtot==8)
{echo $row['Pitch']."<br>";}
else if ($numtot>5)
{echo $row['Pitch'].", ";}
else if ($numtot==5)
{echo $row['Pitch']."<br> ";}
else if ($numtot>1)
{echo $row['Pitch'].", ";}
else
{echo $row['Pitch'];}
$numtot--;
}
}
else {
while ($row = mysql_fetch_array ($result)) {
if ($numtot>9)
{echo $row['Pitch'].", ";}
else if ($numtot==9)
{echo $row['Pitch']."<br>";}
else if ($numtot>5)
{echo $row['Pitch'].", ";}
else if ($numtot==5)
{echo $row['Pitch']."<br> ";}
else if ($numtot>1)
{echo $row['Pitch'].", ";}
else
{echo $row['Pitch'];}
$numtot--;
}
}
}
}
else if ($numtot==12) {
$num1 = rand(3,4);
if ($num1 == 4){
while ($row = mysql_fetch_array ($result)) {
if ($numtot>9)
{echo $row['Pitch'].", ";}
else if ($numtot==9)
{echo $row['Pitch']."<br>";}
else if ($numtot>5)
{echo $row['Pitch'].", ";}
else if ($numtot==5)
{echo $row['Pitch']."<br> ";}
else if ($numtot>1)
{echo $row['Pitch'].", ";}
else
{echo $row['Pitch'];}
$numtot--;
}
}
else {
while ($row = mysql_fetch_array ($result)) {
if ($numtot>10)
{echo $row['Pitch'].", ";}
else if ($numtot==10)
{echo $row['Pitch']."<br>";}
else if ($numtot>7)
{echo $row['Pitch'].", ";}
else if ($numtot==7)
{echo $row['Pitch']."<br> ";}
else if ($numtot>4)
{echo $row['Pitch'].", ";}
else if ($numtot==4)
{echo $row['Pitch']."<br> ";}
else if ($numtot>1)
{echo $row['Pitch'].", ";}
else
{echo $row['Pitch'];}
$numtot--;
}
}
}
?>
由于可能的分布是有限的，已知的，并且不是很多，因此您可以创建它们的散列查找，从中随机选择一个。这段代码未经测试，但原则上应该可以工作:
$dists = array(
array(array(3,3,3)),
array(array(4,3,3),array(3,4,3),array(3,3,4)),
array(array(4,4,3),array(4,3,4),array(3,4,4)),
array(array(4,4,4),array(3,3,3,3))
);
$sandbox = mysql_connect("localhost", "root", "password")
or die(mysql_error());
mysql_select_db("sandbox", $sandbox);
$numtot = rand(9,12);
$sql = "SELECT * FROM pitches ORDER BY RAND() LIMIT $numtot";
$result = mysql_query($sql, $sandbox);
$index = $numtot - 9;
$dist = $dists[$index][array_rand($dists[$index])];
$i = 1;
$j = 0;
$out = '';
while ($row = mysql_fetch_array ($result)) {
$out .= $row['Pitch'];
if ($i == $dist[$j]) {
$out .= '<br>';
$i = 1;
$j++;
} else {
$out .= ',';
$i++;
}
}
echo $out;
相信我，我见过更糟糕的代码，但是您可以使用一个函数来获取$ numtt的值并返回适当的结果，或者如果您熟悉面向对象编程，请考虑策略设计模式。
你们有吉他课吗?:)