PHP flow control if else syntax

if and else syntax

This is a very important chapter and an important syntax in PHP.

[Note] My definition level of this grammar is: tacit writing level. That is, you can write it with your eyes closed if you need it.

Explanation in English:

*if * Pronunciation: [ɪf]
Explanation in Chinese: If

##else Pronunciation: [ɛls]Chinese explanation: Otherwise

We combine if and if...else into four basic grammars, each of which must be memorized.

<?php
if(布尔条件)
   布尔值为真(true)时执行，只能写一行代码;
?>
<?php
if(布尔条件)
   布尔值为真(true)时执行，只能写一行代码;
else
   布尔值为假(false)时执行，只能写一行代码;
?>

<?php
if(布尔条件){
    布尔值为真(true)时执行，可写多行代码;
}
?>
<?php
if(布尔条件){
    布尔值为真(true)时执行，可写多行代码;
}else{
   布尔值为假(false)时执行，可写多行代码;
}
?>

Many people like to buy lottery tickets. Let’s use the process of buying lottery tickets to write an example of if.

<?php
//定义一下中奖变量，变量的值为true,表示中奖了
$zhongjiang = true;
//由于$zhongjiang 结果为true，所以显示了：“买个房子”
//可以改为false试试执行结果，如果为false的话，不会执行echo '买个房子';

if($zhongjiang){
   echo '买个房子';
}
//后续代码
echo '该干嘛干嘛';
?>

In the chapter "3.2.2 Boolean is the Knowledge of the Book of Changes", I gave you a wretched example:

For example, a sentence often mentioned in TV dramas : If I get that beautiful girl (handsome guy), I am willing to die.

Let’s look at the flow chart and it looks like this:

This sentence can be written using computer code:

If I pick up a beautiful girl

Then: I am willing to die
If I don’t pick up a beautiful girl
Then: I am not willing to die This is it:

For the above example, we can completely use if...else... to translate it into code:

<?php
//我们定义一个泡到美女的变量($pao)为false，意思为没泡到
$pao = false;

if($pao)
   //你可以试试在这儿写多行代码会不会报错。
   echo '我愿意去死';
else
   echo '我不愿意去死';

   //if...else执行结束，后续代码
?>
在if...

In

else, we write another example that can be enclosed in curly brackets and have multiple sentences:

<?php
//我们定义一个泡到美女的变量($pao)为true，意思为泡到了
$pao = true;

if($pao){
   echo '我愿意去死';
   echo '林志玲，我爱死你了。';
}else{
   echo '我不愿意去死';
   echo '凤姐，我肯定不会爱你的';
}
//if...else执行结束，后续代码
?>