PHP Operator (2) Detailed explanation of 'String Operator' examples

What are string operators?

Introduction to string operators: The function of string operators is to concatenate two strings to form a new string.

We introduced the arithmetic operators among PHP operators in the previous chapter. I believe you already have some understanding of the "arithmetic operators" among PHP operators. Today, we will give you a detailed introduction to the "String operator" in PHP operators.

In PHP, there are two types of string operators provided for us:

The first one: connection operator, use " ." means that its function is to connect two strings to form a new string.

Second type: assignment connection operator, represented by ".=", which is the combination of "string operator" and "assignment operator" in PHP operators Combination, regarding the assignment connection operator, we will give you a detailed explanation in the following chapters.

So it can also be said that there is only one string operator, which is the first "string concatenation operator", represented by ".".

PS: There is something to note here. In PHP, the "+" sign is only used as an arithmetic operator and cannot be used as a string operator. In the following example, we will compare Explain the difference between the two.

String operator examples

This example is used to compare the difference between "." and "+" signs, when When "." is used, the two strings of variables $a and $b form a new string 1.5a*11, but if the "+" sign is used, PHP will consider this to be an operation. At this time, if there are string types on both sides of the "+" sign, PHP will automatically convert it to an integer type. If there are letters, it will be output as 0. If it is a string starting with a number, the characters will be intercepted. The number at the head of the string is being calculated.

The example code is as follows:

<?

$a="1.5a*1";          //声明一个字符串变量，以数字开头

$b=1;                 //  什么一个整型变量


$ab=$a.$b;            //使用"."运算符将两个变量进行连接

echo $ab."<br/>";

$ba=$a+$b;           ////使用".+"运算符将两个变量进行连接

echo $ba;

?>

The output result is as follows:

It will be fine through the above example You can see the difference between "." and "+", and you can also see the preliminary application of string operators. In the next section, we will introduce in detail the assignment operator in PHP operations.

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