php-output data to the browser (print, Echo, printf, sprintf, etc.)

1. Print(Language structure)

Pirnt-Output string

int print ( string $arg )

Example:

输出：Hello World!print("Hello World!");等价于：print "Hello World!";

Attention:

• Print is a language structure and can enclose the argument list without parentheses;
• Print supports only one parameter ;
• Pirnt always returns 1

2. Echo(Language structure)

echo-output one or more strings

Description

void echo ( string $arg1 [, string $... ] )

Example:

echo "Hello World!";$a = "a";$b = "b";echo $a,$b; // 输出 abecho "a is $a"; // 输出 a is a

Attention:

• Echo is a language structure that does not have to use parentheses to indicate parameters, single quotes, and double quotes can
• Echo accepts the parameter list, which is a number of parameters
• The parentheses cannot be used when echo passes multiple arguments
• echo outputs all parameters, no line break
• Echo has no return value , so efficiency is higher than print

3. printf ()function

printf-Output formatted string
Description

int printf ( string $format [, mixed $args [, mixed $... ]] )

Example:

$num = 2.12; printf("%.1f",$num);  // 输出: 2.1$name = "jack";printf("my name is %s", $name); // 输出：my name is jack

Attention:

• printf () is a function
• printf () returns the length of the output string .

4. sprintf ()function

sprintf ()-Output formatted string
Description

string sprintf ( string $format [, mixed $args [, mixed $... ]] )

Example:

$str = "jack";$name = sprintf("my name is %s", $name);echo $name; // 输出：my name is jack

Attention:

• sprintf () returns the formatted string
• sprintf () does not print output
• Format formats See official website: http://php.net/manual/zh/function.sprintf.php

5. Print_r ()function

print_r ()-Print easy-to-understand information about variables .

Description

bool print_r ( mixed $expression [, bool $return ] )

Attention:

• Print_r () is a function
• If a string, integer, or float is given, the value of the variable is printed .
• If an array is given, the keys and elements are displayed in a certain format.
• object is similar to an array
• Set the return parameter, Print_r () will not print the result, but return its output

Example:

1、打印变量本身：$name = "michael";print_r($name); // 输出：michael2、打印数组：<?php    echo "<pre>";        $a = array (‘a‘ => ‘apple‘, ‘b‘ => ‘banana‘, ‘c‘ => array (‘x‘,‘y‘,‘z‘));    print_r ($a);        echo "</pre>";?>上述代码输出如下结果：    Array    (        [a] => apple        [b] => banana        [c] => Array            (                [0] => x                [1] => y                [2] => z            )    )

The rest, such as vsprintf () and so on are not summed up, the PHP official website (http://php.net) can be viewed.

View method: If you want to see a function on the PHP website and add the function name, press ENTER.

For example:

查看printf函数http://php.net/printf

php-output data to the browser (print, Echo, printf, sprintf, etc.)