将String的True / False布尔值传递给函数参数

Thank you so much for reading and responding if you can.

非常感谢您阅读和回复，如果可以的话。

• In one function I test a condition and make a string 'true' or 'false', which then I make a global variable.
• 在一个函数中，我测试一个条件并使字符串'true'或'false'，然后我创建一个全局变量。
• Then I call another function with that string as the parameter
• 然后我用该字符串作为参数调用另一个函数

• Within that function's if statement, I want to test based off the strings boolean value of 'true' or 'false'

  在该函数的if语句中，我想根据字符串布尔值'true'或'false'进行测试

  $email_form_comments = $_POST['comments']; // pull post data from form
  
  if ($email_form_comments) $comments_status = true;  // test if $email_form_comments is instantiated. If so, $comments_status is set to true
  else $error = true; // if not, error set to true. 
  
  test_another_condition($comments_status); // pass $comments_status value as parameter 
  
  function test_another_condition($condition) {
  
      if($condition != 'true') {    // I expect $condition to == 'true'parameter
        $output = "Your Condition Failed";
        return $output;
       }
  
  }
  

My thinking is that $condition will hold a 'true' value, but this is not so.

我的想法是$条件将保持“真实”值，但事实并非如此。

1 个解决方案

#1

I think the key here is PHP will evaluate empty strings as false and non-empty strings as true, and when setting and comparing booleans make sure to use constants without quotes. Use true or false not 'true' or 'false'. Also, I suggest writing your if statements so they will set alternate values on a single variable, or in the case of a function return an alternate value when the condition fails.

我认为这里的关键是PHP将空字符串评估为false和非空字符串为true，并且在设置和比较布尔值时，请确保使用不带引号的常量。使用true或false不是'true'或'false'。另外，我建议编写if语句，以便它们在单个变量上设置备用值，或者在条件失败时函数返回备用值。

I made some small modifications to your code so that your function will evaluate true

我对您的代码进行了一些小的修改，以便您的函数评估为true

// simulate post content
$_POST['comments'] = 'foo'; // non-empty string will evaluate true
#$_POST['comments'] = ''; // empty string will evaluate false

$email_form_comments = $_POST['comments']; // pull post data from form

if ($email_form_comments) {
  $comments_status = true;  // test if $email_form_comments is instantiated. If so, $comments_status is set to true
} else {
  $comments_status = false; // if not, error set to true. 
}

echo test_another_condition($comments_status); // pass $comments_status value as parameter 

function test_another_condition($condition)
{
    if ($condition !== true) { 
      return 'Your Condition Failed';
    }

    return 'Your Condition Passed';
}