Share an experience on basic PHP syntax

Why should you learn PHP?
I have been learning the development of android applications some time ago. As my learning deepened, I gradually built an image processing system on the android platform. However, I soon discovered an important problem. The Android operating system generally runs on devices with relatively limited hardware resources such as mobile phones and tablets.

Image processing requires a large number of matrix operations. Obviously, it is difficult for handheld devices to meet such requirements. A few days ago I looked at some image processing systems based on the android platform. Among them, a C/S mode image processing system proposed by Stanford University's EE368 laboratory aroused my great interest. The process of this system is as follows:

That is to say: although our handheld device resources are limited, we can send the images and other information that need to be processed to the remote server. The image is processed and then the processed information is sent to our mobile phone. PHP plays an important role in it. From this, I started my study of PHP.

The following is my personal summary of PHP syntax: (Since I have learned C/C/JAVA/HTML/MATLAB/ANDROID, etc., I will not give examples where PHP and C languages ​​are similar)

PHP basic syntax example learning (1)

1. Variable name

$abc=1; $_abc=12.5 ; $_ABC2TR=TURE;(must start with $)

2. Data type

boolean (Boolean type) is understood as true and false type

bo=TRUE; $bo=FALSE;

integer (integer type)

$bo=1; $bo=-12;

float (floating point type, also as "double") is understood as a decimal number or EN Word”;

(Use dot “.” to add strings)

array(array)

$bo=array(1,2,3,4 ); $bo=array(“A”=>1 , "B" =>2);

3. Output statement

Output statement: echo

4. Conditional statement if Usage

(Same as C language)else if;else

5. Examples of usage of conditional statement switch

(same as C language) case, break, etc.

6. Loop Usage examples of statements for, while

(Same as C language) break

7. Examples of the definition and use of arrays

Definition: Use array

$arr = array (3,5,7,9,6);
$arr = array("id"=>2,"title"=>3);//类似C语言中的结构体

Use: use [ ] square brackets

<?php
$arr1 = array(3,5,7,9,6);
$arr2 = array("id"=>2,"title"=>"hello
 array!");
echo$arr1[0];//输出3
echo"<br>";//换行
echo$arr2[&#39;title&#39;];//输出helloarray!
$arr2[&#39;title&#39;]="Hi,Nanjing!";//赋值
echo"<br>";//换行
echo$arr2[&#39;title&#39;];//输出Hi,Nanjing!
?>

8. Function declaration and calling examples

Declaration: function keyword

function  name_fun(var1,var2,…){
       return var1+var2;
}

CallVar3= name_fun(var1,var2,…);

Example:

function_11number(){
    for($i=1;$i<100;$i++)
    {
       if($i%11==0){
          echo$i."<br>";
       }
    }
}
_11number();
输出1~100以内11的倍数。

9. File reference include("xxx .php"), require("xxx.php"), require_once() and include_once()

include() statement will only read the file to be included when it is executed, and PHP will process it. The processor will reprocess it every time it encounters an include() statement.

require_once() and include_once() statements correspond to require() and include() statements respectively. The require_once() and include_once() statements are mainly used when multiple files need to be included, which can effectively avoid errors in repeated definitions of functions or variables caused by including the same piece of code. Thank you everyone for reading, I hope you will benefit a lot.

This article is reproduced from: https://blog.csdn.net/NUPTboyZHB/article/details/7912483

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