Detailed introduction to the ternary operator in php

Welcome everyone to learn php hereternary operation symbol! Below is the exciting content we have compiled for you. I hope everyone can learn here! Ternary Operator Syntax: Condition? Result 1: Result 2 Description: The position in front of the question mark is the condition for judgment. If the condition is met, the result is 1, and if it is not met, the result is 2. Let’s discuss this in detail below.

$if_summary = $row['IF_SUMMARY']==2?'是':'否';

Later Baidu found out that it is PHP's ternary operator

This sentence means that the function of

if($row['IF_SUMMARY']==2){
$if_summary="是";
}else{
$if_summary="否";
}

is the same as "if.. .else" process statement is consistent, it is written in one line, the code is very concise and the execution efficiency is higher.

Appropriate use of the ternary operator in PHP programs can make scripts more concise and efficient.

The code format is as follows:

(expr1) ? (expr2) : (expr3);

Explanation: If the condition "expr1" is true, execute the statement "expr2", otherwise execute "expr3".

To achieve the same function, if you use conditional process statements, you need to write multiple lines of code:

if(expr1) {
expr2;
} else {
expr3;
}

It can be seen that the goodness of the ternary operator mentioned above is not an exaggeration. However, in most cases we only use the ternary operator when the code is relatively simple, that is, when the execution statement is only a single sentence. For example:

1$a>$b ? print "a is greater than b" : print "a is less than b";

In fact, the ternary operator can be extended to use, when the conditions are set Whether it is true or not, the execution statement can be more than one sentence. Try the following format:

(expr1) ? (expr2).(expr3) : (expr4).(expr5);

We can clearly see that multiple execution statements can be used using the string operator symbol (". ") are connected, and each execution statement is surrounded by small angle brackets to indicate that it is an independent and complete execution statement. After this expansion, its function is closer to the "if...else" process statement.

At the same time, the ternary operator can also be used nested. For example, when a is greater than b: if a is less than c, then x=c-a otherwise x=a-c; otherwise when a is less than b: if b is less than c, then 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 the nested ternary operator is not very good, and there may be problems with maintaining the code in the future. However, compared with process statements such as "if...else", in the above situation, it is indeed too It's concise, and that's its allure.

For those who like to be lazy and pursue code simplicity, using the ternary operator to replace the if process statement should be an excellent choice. Even if there is no need to consider any "element" other than the conditional sentence in the "ternary", using the ternary operator is still more concise than the if statement. The syntax of the following statements is correct, they omit the second or third "element" in a small unquote manner:

2$a>$b ? print "Yes" : "";
$a>$b ? '': print 'No';

It should be noted: when using the ternary operator, it is recommended to use the print statement Replaces the echo statement.

Pay attention to the understanding of the following series of statements:

$str = $_GET['abc'] ? 'wangjinbo' : 'wjb';

This cannot be understood as: when $str is equal to $_GET['abc'], the assignment is 'wangjinbo', otherwise the assignment is 'wjb' ;Because one: == should be used to judge equality; Reason two: The syntax of the ternary operator is as shown above: (expr1) ? (expr2) : (expr3), obviously the above binary, ternary 'wangjinbo' or ' wjb' cannot alone form a meaningful expression;

The correct understanding is: when $_GET['abc'] is empty (that is, whether, '' in PHP, null, 0, undifine, are equivalent to the Boolean value false), assign $str to 'wangjinbo', otherwise assign it to 'wjb';

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