Let's talk about knowledge about PHP printing methods

PHP is an open source dynamic scripting language that is widely used in Web development. Its popularity even exceeds traditional static web development languages. In PHP development, printing method is a very important knowledge point. This article will introduce you to the relevant knowledge about PHP printing method.

1. Echo statement

The most commonly used PHP printing method is the echo statement, which can output a piece of text in the browser. The syntax is as follows:

echo 输出的内容;

The output content can be any data type such as strings, numbers, etc., and can also contain HTML tags. For example:

echo "Hello World!"; // 输出 Hello World!
echo "<h1 id="标题">标题</h1>"; // 输出一个标题

echo statement can be used to output multiple contents at one time, just separate them with commas. For example:

echo "这是一个","字符串","的例子"; // 输出：这是一个字符串的例子

2. Print statement

The print statement is similar to the echo statement and can be used to output content in the browser. The difference is that the print statement can only output a string. And will return a value (1). The syntax is as follows:

print 输出的内容;

Among them, the output content must be of string type. For example:

print "Hello World!"; // 输出 Hello World!

3. printf function

The printf function is a formatted output method that can output content according to a customized format. The syntax is as follows:

printf(格式化字符串,输出内容1,输出内容2,...);

Among them, the format string is used to define the output format. The output content can be any data type such as strings, numbers, etc., and can also contain HTML tags. For example:

$name = "张三";
$age = 18;
printf("我的名字是：%s，年龄是：%d。",$name,$age); // 输出：我的名字是：张三，年龄是：18。

In the format string, you can use different placeholders to represent different types of data. Commonly used placeholders are:

• %s: represents String type data;
• %d: represents integer type data;
• %f: represents floating point type data;
• %c: represents character type Data;
• %b: represents binary type data;
• %o: represents octal type data;
• %x: represents hexadecimal type data.

For example:

$num = 123;
printf("%b<br>",$num); // 输出二进制数：1111011
printf("%o<br>",$num); // 输出八进制数：173
printf("%x<br>",$num); // 输出十六进制数：7b

4. var_dump function

The var_dump function can print out the detailed information of a variable, including type, length, value, etc. The syntax is as follows:

var_dump(变量名);

Among them, the variable name is the name of the variable that needs to be printed. For example:

$num = 123;
var_dump($num); // 输出 int(123)

5. print_r function

The print_r function is used to print out the structural information of an array, object, etc., and is very suitable for debugging and debugging errors. The syntax is as follows:

print_r(变量名);

Among them, the variable name is the name of the variable that needs to be printed. For example:

$arr = array("one","two","three");
print_r($arr);

The output result is as follows:

Array
(
    [0] => one
    [1] => two
    [2] => three
)

The above are the commonly used printing methods in PHP. By mastering these methods, you can better develop and debug PHP.

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