PHP conditional operator

Ternary operator syntax ： Conditions ? result 1 : result 2 explain ： The position in front of the question mark is the condition of judgment , If the conditions are met, the result is 1, Results when not satisfied 2. Let's discuss it in detail .
When I was changing my paper online today, I encountered a sentence that I couldn't understand ：
$if_summary = $row{[}^{\prime }I{F}_{S}UMMAR{Y}^{\prime }]==2{?}^{\prime }{yes}^{\prime }{:}^{\prime }{no}^{\prime };afterCome\; onhundreddegreeafterHairpresentyesPHPOf3、\; ...\; andelementshipmentcountoperatorthissentencewordOfIt\; meansthinkingJustetc.Onyesif($row[‘IF_SUMMARY’]==2){
$if_summary=“ yes ”;
}else{
$if_summary=“ no ”;
}
The functions of ternary operators are the same as “if…else” Consistent process statements , It's written in one line , The code is very concise 、 More efficient execution .
stay PHP Proper use of ternary operators in the program can make the script more concise 、 Efficient .
The code format is as follows ：(expr1) ? (expr2) : (expr3);
explain ： If the condition “expr1” establish , Then execute the statement “expr2”, Otherwise execution “expr3”.
Implement the same functionality , If you use conditional flow statements , You need to write multiple lines of code ：

if(expr1) {

expr2;
} else {
expr3;
}
so , The advantages of the ternary operators mentioned above are not exaggerated . But , In most cases, we only use ternary operators when the code is relatively simple , That is, when the execution statement is only a single sentence . Such as ：

$a>$b ? print “a Greater than b” : print “a Less than b”;
in fact , Ternary operators can be extended to , When the set conditions are true or false , The execution statement can be more than one , Try the following format ：
(expr1) ? (expr2).(expr3) : (expr4).(expr5);
We see very clearly , Multiple execution statements can use string operation symbols （“.”） Connect , Each execution statement is enclosed by small angle brackets to indicate that it is an independent and complete execution statement . After this expansion, its function is closer to “if…else” Process statement .
At the same time, ternary operators can also be nested . for example ,a Greater than b When established ： If a Less than c, that x=c-a otherwise x=a-c; otherwise a Less than b When established ： If b Less than c, that x=c-b otherwise x=b-c：
$a>$b ? $x=($a<$c ? $c-$a : $a-$c) : $x=($b<$c ? $c-$b : $b-$c);
The readability of ternary operators used in nesting is not very good , Maintenance of the code in the future is likely to be problematic , But compared with “if…else” Process statements like , Under the above circumstances , It's really too concise , This is what makes it attractive .
For people who like to be lazy and pursue simple code , Replace with ternary operator if Process statements should be a great choice . Even without considering “ Three yuan ” Any one except the conditional sentence in “ element ”, Using the ternary operator is still better than if Concise statement . The syntax of the following statement is correct , They omit the second or third... In a way that deciphers the quotation marks “ element ”：

$a>$b ? print “Yes” : “”;
$a>$b ? ‘’: print ‘No’;
It should be noted that ： When using ternary operators , It is recommended to use print Statement substitution echo sentence .
Pay attention to the understanding of the following sentences ：
?
1

$str = ${}_{G}ET{[}^{\prime }ab{c}^{\prime }]{?}^{\prime }wangjinb{o}^{\prime }{:}^{\prime }wj{b}^{\prime };thisinNocanThe\; reason\; isExplainby：When$str be equal to ${}_{G}ET{[}^{\prime }ab{c}^{\prime }]when,Fuvalue{by}^{\prime }wangjinb{o}^{\prime }nobeFuvalue{by}^{\prime }wj{b}^{\prime };becausebyOne：sentencebreakphaseetc.Should\; beTheuse==;becauseprimaryTwo：3、\; ...\; andelementcountoperatorOflanguageLawyesSuch\; asOnthein：(expr1)?(expr2):(expr3),displayhoweverOnNoodlesOfTwoelement,3、\; ...\; and{element}^{\prime }wangjinb{o}^{\prime }{or}^{\prime }wj{b}^{\prime }NocansinglesinglestructurebecomeOneindividualYesIt\; meansThe\; righteousOfsurfacereachtype;justindeedThe\; reason\; isExplainyes：When$_GET[‘abc’] It's empty （ Whether or not ,PHP in ‘’,null,0,undifine, Are equivalent to Boolean values false） when , take $str The assignment is ’wangjinbo’, Otherwise, it is assigned as ’wjb’;
The above is the whole content of this article , I hope you like it .