快速PHP问题

Question

I have the following excerpt:

if (empty($last_db_error)) {
    echo "OK";
} else {
    echo "Error activating subscription.";
    echo "{$last_db_error}";
}

The problem is that "{$last_db_error}" is not shown, unless I use just $last_db_error , without the quotes and brackets. Am I missing something here? Isn't the above syntax correct?

Answer 1

The brackets and the quotes are useless in this case.

if (empty($last_db_error)) {
    echo "OK";
} else {
    echo "Error activating subscription.";
    echo $last_db_error;
}

Will do the job perfectly.

BTW, even if you do can put $vars insides quotes in PHP, this is not recommended because :

• It works for double quotes only, single quotes will display the var name, which leads to error.
• It slows down the string parsing.

It's much more appropriate to concatenate variables using the dot operator :

if (empty($last_db_error)) {
    echo "OK";
} else {
    echo "Error activating subscription.\n".
          $last_db_error;
}

And as soon as you have a lot of text to deal with, I urge you to use the PHP alternative syntax . EG :

<?php if (empty($last_db_error)): ?>
        OK
<?php else : ?>
        Error activating subscription.
        <?php echo $last_db_error; ?>
<?php endif; ?>

Answer 2

Is $last_db_error a string or object? If it is a string it should display properly between double quotes using curly braces (like you posted above) so the code seems correct.

Place a var_dump($last_db_error) in the else statement and see what it outputs.

Answer 3

Just use

echo $last_db_error; 

the rest is not needed here.

Answer 4

The curly brackets are used to evaluate more complex variable names. If you want the curly brackets in the output, then try escaping the them, like so:

if (empty($last_db_error)) {
    echo "OK";
} else {
    echo "Error activating subscription.";
    echo "\{$last_db_error\}";
}

Answer 5

For me it works ok:

<?php
$last_db_error = "LLLLLLLLLLLL";
echo "{$last_db_error}";

It shows me LLLLLLLLLLLL

Answer 6

也许您正在使用某种模板系统来解析{ .... }内部的所有内容？

Answer 7

The simpliest way is:

echo $last_db_error;

For some situations try these:

 echo "${last_db_error}";
 echo ${'last_db_error'};

Here is a good article regarding php variable names: curly braces