请检查我的代码：
<?php
$operarors = array( '+', '-', '*' );
$randOperator = array($operarors[rand(0,2)], $operarors[rand(0,2)]);
$num1 = rand(0,10);
$num2 = rand(0,10);
$num3 = rand(0,10);
$result = $num1.$randOperator[0].$num2.$randOperator[1].$num3;
echo "The math: $num1 $randOperator[0] $num2 $randOperator[1] $num3 = $result";
?>
在上面的代码中，我没有得到结果总数。
假设我得到3+4*5，输出应该是23，但它显示字符串3+4*5。
请帮帮我。
你不能像这样连接运算符。我建议做这样的事情：
<?php
function operate($op1, $operator, $op2) {
switch ($operator) {
case "+":
return $op1 + $op2;
case "-":
return $op1 - $op2;
case "*":
return $op1 * $op2;
}
}
$operators = array( '+', '-', '*' );
// performs calculations with correct order of operations
function calculate($str) {
global $operators;
// we go through each one in order of precedence
foreach ($operators as $operator) {
$operands = explode($operator, $str, 2);
// if there's only one element in the array, then there wasn't that operator in the string
if (count($operands) > 1) {
return operate(calculate($operands[0]), $operator, calculate($operands[1]));
}
}
// there weren't any operators in the string, assume it's a number and return it so it can be operated on
return $str;
}
$randOperator = array($operators[rand(0,2)], $operators[rand(0,2)]);
$num1 = rand(0,10);
$num2 = rand(0,10);
$num3 = rand(0,10);
$str = "$num1 $randOperator[0] $num2 $randOperator[1] $num3";
echo "$str = ", calculate($str), PHP_EOL;
正如@AndreaFaulds所说，或者使用回调：（尽管使用 array_reduce 和所有这些数组指针魔术都是不必要的）。
<?php
$ops = [
'+' => function ($op1, $op2) { return $op1 + $op2; },
'*' => function ($op1, $op2) { return $op1 * $op2; },
'-' => function ($op1, $op2) { return $op1 - $op2; }
];
$nums = [rand(0, 10), rand(0, 10), rand(0, 10)];
$operators = [array_rand($ops), array_rand($ops)];
$initial = array_shift($nums);
$result = array_reduce($nums, function ($accumulate, $num) use (&$operators, $ops) {
return $ops[each($operators)[1]]($accumulate, $num);
}, $initial);
请注意，[]短数组语法的版本要求为 PHP 5.4+。
您应该使用 + 运算符而不是 . 运算符。这。只是将其粘贴在一起，就好像值是字符串一样。