Summary of usage examples of colon, endif, endwhile, and endfor in PHP

We often see a lot of strange PHP syntax in the templates of blogging programs such as wordpress, such as:

<?php if(empty($GET_[&#39;a&#39;])): ?> 
<font color="red">空的</font> 
<?php endif; ?>

For A considerable number of PHP enthusiasts have never seen it before. What are these? Could it be that the blog developers themselves created a template language that imitates PHP?
No, in fact, these are PHP syntax, but they are not commonly used. These are alternative syntaxes for PHPProcess Control.
Here I will give you a detailed explanation of the alternative syntax of PHP process control. What is alternative syntax?
Simply put, they are some alternative ways of writing grammar.
What are the alternative syntaxes in PHP?
Flow control (including if, while, forforeach, switch) statements have alternative syntax.
Basic form of alternative syntax:
Replace the left curly brace ({) with a colon (:), replace the right curly brace (}) with endif;, endwhile;, endfor;, endforeach; and endswitch;
For example:

<?php if ($a<0): ?> 
是负数拉 
<?php endif; ?> 
上面的语句等同于 
<?php if （$a<0）{ ?> 
是负数拉 
<?php } ?>

Why is it almost invisible in pure PHP code?
These syntaxes are a bit inconsistent with the tradition of the C family and are a bit alternative. Everyone is not used to this syntax, and it is not very convenient.
Everyone is not used to it, and what is the use of such an alternative? Does your balls hurt?
Existence is reasonable, and it has its own uses. The place where these syntaxes can be used is in the code of a mixed PHP and HTML page. The benefits are as follows:
1. Make the HTML and PHP mixed page code cleaner and neater.
What those friends who are obsessed with coding are most afraid of is messy mixed code. With these alternative syntaxes without braces, all friends who love cleanliness will be so happy that they pee.
2. The process control logic is clearer and the code is easier to read
If you want to change someone else's PHP and HTML mixed code, open it and find it, I will wipe it! What a fucking rubbish! If alternative syntax is used, I think no matter how rubbish the program developer is, his writing will not be too messy.
3. Some friends who have transferred from ASP and other basic language families will find it easier to use PHP.
Talking for a long time is useless, how about we get something to do? How to use this thing?
According to the previously described usage, the alternative syntax for the if statement is as follows:

<?php if ($a == 5): ?> 
<p>等于5</p> 
<?php elseif ($a == 6): ?> 
<p>等于5</p> 
<?php else: ?> 
<p>不是5就是6</p> 
<?php endif; ?>

while alternative syntax:

<?php while (expr): ?> 
<li>循环点什么</li> 
<?php endwhile; ?>

for alternative syntax:

<?php for (expr1; expr2; expr3): ?> 
<li>循环点什么</li> 
<?php endfor; ?>

foreach alternative syntax:

<?php foreach (expr1): ?> 
<li>循环点什么</li> 
<?php endforeach; ?>

switch alternative syntax:

<?php 
switch ($i): 
case 0: 
echo "i equals 0"; 
break; 
case 1: 
echo "i equals 1"; 
break; 
case 2: 
echo "i equals 2"; 
break; 
default: 
echo "i is not equal to 0, 1 or 2"; 
endswitch; 
?>

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