Detailed introduction to PHP knowledge points

Problem In javascript, both integers and floating-point numbers belong to the Number data type (one of the simple data types). We often find that when printing a floating-point number such as 1.0, the result is 1 instead of 1.0. This is due to saving the floating-point number. Points take up twice as much memory as storing integer values, so ECMAScript wastes no time converting floating point numbers to integers. Although the above situation makes patients with obsessive-compulsive disorder a little uncomfortable, it is not a big mistake anyway. The next situation will be very scary. For example, when we calculate 0.1 plus 0.2, the output result is not 0.3, but 0.3000000000000004. what the fuck? ! For children who encounter this situation for the first time, do you feel that your world view has been challenged? The reason was so I quickly opened the book to save my soul and body, and found that it was clearly written in the book: ECMAScrip is based on IEEE754 numerical floating point calculation. If you don’t know what IEEE754 is, click here. This numerical calculation method will save the value as Binary is then calculated. Since floating point numbers are infinite when expressed in binary, there will be

1. javascript floating point value operation bug# when performing arithmetic calculations.

##Introduction: In javascript, both integers and floating point numbers belong to the Number data type (one of the simple data types). We often It is found that the result of printing a floating point number such as 1.0 is 1 instead of 1.0. This is because the memory space for storing floating point numbers is twice that of storing integer values, so ECMAScript will lose no time in converting floating point numbers into integers. Although the above situation makes patients with obsessive-compulsive disorder a little uncomfortable, it is not a big mistake anyway. The next situation will be very scary. For example, when we calculate 0.1 plus 0.2, the output result is not 0.3, but 0.3000000000000004. what the fuck? ! The children's shoes who encountered this situation for the first time are

2. Brainfuck Compiler on PHP

Introduction:: This article mainly introduces Brainfuck Compiler on PHP. Students who are interested in PHP tutorials can refer to it.

3. How to call functions within PHP strings_PHP tutorial

Introduction: Calling within PHP strings Functional way. {$o0_0o{phpinfo()}} 1 {$Let me go [phpinfo()]} ${~-~phpinfo()} ${0e0+phpinfo()} What fuck? ?php I am a good person$_$ {$_{pHPINfo(~@-@~-$$In short, I am a good person)}} I am a good person; ? I am simple

4. How to use PHP to Ping an address_PHP tutorial

Introduction: How to use PHP to ping an address. How to use PHP to ping an address if(($server == 127.0.0.1) | | ($server == localhost) | | ($server == getenv("SERVER_ADDR"))) { echo " "; echo " Fuck Off! "; echo " "; exit; } el

5. Questions about die

Introduction : Questions about dieThis is my code if If there is no echo, then the entire web page is HTTP Error 500 (Internal Server

##6.

Please provide the steps to write PHP native code in the {dede:sql} tag script

Introduction: How to write php native code in {dede:sql} tag script! {dede:sql sql='...' runphp='yes'}echo 'fuck'; {/dede:sql}It’s useless for me to write like this. How can I write PHP native code in the {dede:sql} tag script??------Solution----------- ---------- The following is the php application in dede, I hope it will be helpful to you

7.

I really don’t know where to post it so I have to post it here: About linux6.1 enterprise version configuration php operation

Introduction: I really don’t know where to post it so I have to post it here: Regarding the configuration of linux6.1 enterprise version to run php, I installed a desktop version of linux 6.1, and apache was also installed. The startup is normal, but the PHP code cannot be interpreted, that is, there is a test.php in /etc/www/html/. The code is very simple, just echo 'fuck'; but the browser (Firefox) outputs all the codes as they are. and is not parsed if

8. Brother, I want to implement such a function, how to implement it

Introduction: I want to implement such a function, how to implement it? I want a static variable to be 0 when accessed for the first time, and +1 for each subsequent access. I write this on my page: if(!isset($tmp)) static $tmp=0;$tmp++;echo 'fucking number:'.$tmp; doesn't work, $tmp changes back to 0 every time. How to make $tmp set to 0 only once?------Solution

9. PHP inserts keywords into strings at random positions

Introduction: PHP inserts keywords into strings at random positions $times = 4; //Keyword frequency $keyword = "[fuck]"; //Keyword to be replaced $str = "Brown is dull aluminum sulfate Zhonghuo right Chinese and Western medicine three Alashankou place can see las resolution Oh iasfls.sdmflaskdfThe law in Los Angeles is stuck ohiuoi020990 The time is stretched and crazy happened";$strlen = mb_strlen($st

##10. Ask for {dede:sql} How to write PHP native code in tag script! Solution

## Introduction: How to write PHP native code in {dede:sql} tag script! ='...' runphp='yes'} echo 'fuck'; {/dede:sql} It's useless for me to write like this. How can I write php native code in the {dede:sql} tag script??------Solution-----------

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