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: [?f]
Explanation in Chinese: If

##else Pronunciation: [?ls]Chinese explanation: Otherwise

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

<?php
if(布爾條件)
   布爾值為真(true)時(shí)執(zhí)行，只能寫(xiě)一行代碼;
?>
<?php
if(布爾條件)
   布爾值為真(true)時(shí)執(zhí)行，只能寫(xiě)一行代碼;
else
   布爾值為假(false)時(shí)執(zhí)行，只能寫(xiě)一行代碼;
?>

<?php
if(布爾條件){
    布爾值為真(true)時(shí)執(zhí)行，可寫(xiě)多行代碼;
}
?>
<?php
if(布爾條件){
    布爾值為真(true)時(shí)執(zhí)行，可寫(xiě)多行代碼;
}else{
   布爾值為假(false)時(shí)執(zhí)行，可寫(xiě)多行代碼;
}
?>

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

<?php
//定義一下中獎(jiǎng)變量，變量的值為true,表示中獎(jiǎng)了
$zhongjiang = true;
//由于$zhongjiang 結(jié)果為true，所以顯示了：“買(mǎi)個(gè)房子”
//可以改為false試試執(zhí)行結(jié)果，如果為false的話，不會(huì)執(zhí)行echo '買(mǎi)個(gè)房子';

if($zhongjiang){
   echo '買(mǎi)個(gè)房子';
}
//后續(xù)代碼
echo '該干嘛干嘛';
?>

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
//我們定義一個(gè)泡到美女的變量($pao)為false，意思為沒(méi)泡到
$pao = false;

if($pao)
   //你可以試試在這兒寫(xiě)多行代碼會(huì)不會(huì)報(bào)錯(cuò)。
   echo '我愿意去死';
else
   echo '我不愿意去死';

   //if...else執(zhí)行結(jié)束，后續(xù)代碼
?>
在if...

In

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

<?php
//我們定義一個(gè)泡到美女的變量($pao)為true，意思為泡到了
$pao = true;

if($pao){
   echo '我愿意去死';
   echo '林志玲，我愛(ài)死你了。';
}else{
   echo '我不愿意去死';
   echo '鳳姐，我肯定不會(huì)愛(ài)你的';
}
//if...else執(zhí)行結(jié)束，后續(xù)代碼
?>