首先，如果这句话措辞不当，我很抱歉，因为我是代码初学者。
我目前正在学习一门在线计算机科学课程，但我对如何完成一小部分感到困惑。我们需要为此活动使用数组，其中用户有多个选择，每个不同的选择都有不同/唯一的文本输出。一切都很好，只是我需要一个选项来选择随机选择，但我有点困惑。你可以从我的代码中看到选项1-8。我希望它随机选择其中一个选项。
这是我的代码：
<?php
$train[0] = "Canada";
$train[1] = "Sahara Desert";
$train[2] = "Russia";
$train[3] = "Chernobyl";
$train[4] = "United States";
$train[5] = "North Korea";
$train[6] = "Germany";
$train[7] = "Hawaii";
?>
<!DOCTYPE html>
<html>
<head>
Took out everything here, it's not important.
</head>
<body>
<center>
<h1>Vacation Time!</h1>
<h4>You and your family just won the lottery! You all want to go on vacation, but nobody can agree where to go. Inside each train cart has a card with a location written on it. Whatever you find is where you're going! </h4>
<form name="form1" action="activity-2-7-arrays-a.php" method="post">
<label>Which cart on the train do you want to choose?</label>
<br>
<select name="cart" required>
<option value="1">First Cart</option>
<option value="2">Second Cart</option>
<option value="3">Third Cart</option>
<option value="4">Fourth Cart</option>
<option value="5">Fifth Cart</option>
<option value="6">Sixth Cart</option>
<option value="7">Seventh Cart</option>
<option value="8">Eight Cart</option>
<option value="show">Show all options</option>
<option value="any">Choose Randomly</option>
<br>
</select><br/>
<input type="submit" name="subButton" class="subButton" value="Go!"/><br/>
</form>
<h1><u>Final Results</u></h1>
<?php
if($_POST['subButton']) {
$cart = $_POST['cart'];
$roll = rand(1,9);
if($cart == show) {
for($x = 1; $x <= 9; $x++) {
echo "<p> You could have ender up in... </p>";
echo "<h2> " . $train[$x] . "</h2>";
}
return;
}
echo "<h2>"."Well, it looks like you're going to " . $train[$cart] . "! Have fun! </h2>";
}
return;
if ($cart == $roll) {
}
echo "<h2>"."Can't handle the pressure? You were selected to go to " . $train[$roll] . "! Have fun! </h2>";
?>
我肯定它也有点乱。希望你能理解我的意思。如果你能向我解释答案，那将是非常有帮助的。谢谢：）
不管用户的选择如何，您都会随机生成一个值，并将其与用户的选择和其他奇怪的事情进行比较。
<?php
if($_POST['subButton']) {
$cart = $_POST['cart'];
$roll = rand(1,9);
在检查用户是否选择"随机选择"之前，您正在生成一个随机值，为什么要生成1到9之间的随机值？$train数组以索引0开始，以索引7结束。
if($cart == show) {
字符串需要加引号。
for($x = 1; $x <= 9; $x++) {
再次，由于您的数组索引，将$x从1循环到9毫无意义。
echo "<p> You could have ender up in... </p>";
echo "<h2> " . $train[$x] . "</h2>";
当$x达到8时将失败，因为$train中的最后一个索引为7。
}
return;
}
echo "<h2>"."Well, it looks like you're going to " . $train[$cart] . "! Have fun! </h2>";
}
return;
所以，若用户并没有选择"显示所有选项"，你们会显示他选择的位置。如果用户选择"随机选择"，这将失败，因为$cart的值为"any"，而$train['any']不存在。
这是具有正确逻辑的代码。
<?php
if($_POST['subButton']) {
$cart = $_POST['cart'];
if ($cart == 'any') {// Check if user selected 'Choose Randomly'
$roll = rand(0, 7);
echo "<h2>"."Can't handle the pressure? You were selected to go to " . $train[$roll] . "! Have fun! </h2>";
}
else {
if ($cart == 'show') { // If user selected 'Show all options'
echo "<p> You could have ender up in... </p>";
for($x = 0; $x <= 7; $x++) {
echo "<h2> " . $train[$x] . "</h2>";
}
}
else { // User selected cart so show him chosen location
echo "<h2>"."Well, it looks like you're going to " . $train[$cart] . "! Have fun! </h2>";
}
}
}
?>
以下是代码中的一些问题
- 我们
return是从哪里来的，为什么 - 没有关闭的html标记
我会这样修改php代码的最后一部分：
<?php
if ($_POST['subButton']) {
$cart = $_POST['cart'];
$value = intval($cart);
$roll = mt_rand(1, 8); // mt_rand() has more entropy than rand()
if ($cart == 'show') {
// show target locations (according the OP-source)
for($x = 1; $x <= 8; $x++) {
echo "<p> You could have ender up in... </p>";
echo "<h2> " . $train[$x-1] . "</h2>";
}
} else if ($value > 0 && $value <= 8) {
echo "<h2>"."Well, it looks like you're going to " . $train[$value-1] . "! Have fun! </h2>";
// idk why it needed, but move it here
if ($value == $roll) {
}
} else if ($cart == 'any') {
echo "<h2>"."Can't handle the pressure? You were selected to go to " . $train[$roll-1] . "! Have fun! </h2>";
} else {
// $_POST['cart'] has something wrong
}
}
?>
<!-- lines below was added to close html-tags -->
</body>
</html>
您要查找的是array_rand():
$random = array_rand($train);
不要使用rand()，而是使用mt_rand()，因为PHP DOCUMENT的字面意思是
mt_rand--生成更好的随机值
关于php代码，您有很多错误。下面的php代码应该是这样的：
<?php
if($_POST['subButton'])
{
$cart = $_POST['cart'];
$roll = mt_rand(0,7);
//0-7 because those are the values you inserted into
//the $train[] array
if($cart == 'show') {
//another correction here, it has to be 0-7
for($x = 0; $x <= 7; $x++) {
echo "<p> You could have ender up in... </p>";
echo "<h2> " . $train[$x] . "</h2>";
}
}
else if ($cart!='any')
{
"<h2>Well, it looks like you're going to " . $train[$cart] . "! Have fun! </h2>";
}
else //took out return and placed an else
{
echo "<h2>Well, it looks like you're going
to " . $train[$cart] . "! Have fun! </h2>";
}
?>