PHP and printing out whitespace?

Question

我想知道如何在下面的代码中打印出空格。

<?php echo "$first_name", "$last_name" ; ?>

Answer 1

Just, well, add whitespace to your output?

<?php echo "$first_name $last_name with     some    whitespace" ; ?>

Sometimes, it the obvious answer is right - even in PHP!

Answer 2

如果要连接多个不带双引号的字符串（例如，使用单引号时）：

$string = $first_name . ' ' . $last_name; // The dot is a concatenation operator

Answer 3

<?php 
echo "$first_name $last_name"; 
?>

Answer 4

Notice that when you use ' any var aren't display, with " does.
So, good is:
<?php echo "$first_name $last_name" ; ?>
bad
<?php echo '$first_name $last_name' ; ?>

Answer 5

如果要继续使用逗号：

<?php echo  $first_name, ' ', $last_name; ?>