Spaceship operator in PHP7: How to compare the size of two expressions?

Spaceship operator in PHP7: How to compare the size of two expressions?

In PHP7, a new operator is introduced, called the Spaceship operator (). This operator compares the size of two expressions and returns the result suitable for sorting purposes.

Traditionally, when comparing the size of two expressions in PHP, we use comparison operators (>,

The space boat operator is a combination operator that first compares the size of two expressions. If the expression on the left is less than the expression on the right, -1 is returned; if the expression on the left is equal to the expression on the right, 0 is returned; if the expression on the left is greater than the expression on the right, 1 is returned. In this way, we can determine the size relationship between two expressions by judging the sign of the return value.

The following is a simple example that demonstrates how to use the space boat operator to compare the size of two numbers:

$a = 10;
$b = 5;

$result = $a <=> $b;

if ($result == -1) {
    echo "a 小于 b";
} elseif ($result == 0) {
    echo "a 等于 b";
} else {
    echo "a 大于 b";
}

In the above code, we define two variables $a and $b , assigned values ​​of 10 and 5 respectively. Then, use the spaceship operator $a $b to compare the sizes of the two variables and assign the result to the variable $result.

Finally, we use conditional statements to determine the value of the variable $result, determine the size relationship between the two expressions based on their positive and negative values, and output the corresponding results.

In addition to comparing numbers, the space boat operator can also be used to compare other types of expressions such as strings and arrays. Here is an example of comparing two strings:

$str1 = "hello";
$str2 = "world";

$result = $str1 <=> $str2;

if ($result == -1) {
    echo "str1 小于 str2";
} elseif ($result == 0) {
    echo "str1 等于 str2";
} else {
    echo "str1 大于 str2";
}

In this example, we compare the size of two string variables $str1 and $str2. Similarly, we use the space boat operator $str1 $str2 to compare the two strings and output the corresponding comparison result based on the returned result.

Through the above examples, we can see that the space boat operator is concise and flexible, making it more convenient and intuitive to compare the sizes of two expressions. In actual development, the space boat operator can help us simplify the code and improve the readability of the code.

To sum up, the space boat operator in PHP7 provides us with a new way to compare the sizes of two expressions. The spaceship operator makes comparison operations more concise and flexible by returning a result suitable for sorting purposes. We can use the spaceship operator on different data types and perform corresponding logical processing based on the return value. In actual development, reasonable use of the spaceship operator will help improve the efficiency and readability of the code.

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