Basic operations of php

This article mainly introduces the basic operations of php, which has certain reference value. Now I share it with everyone. Friends in need can refer to it

php basic knowledge

array function

• count($arr) Calculate the number of elements in the array

• ##print_r($arr) Print the array

• Iterate array

• for index traversal

• foreach() iterate array

• foreach(
  item){} Traverse the values ​​of the array

• foreach (

  ##key=>$value) Traverse the keys and values ​​of the array

Array sorting
sort(); Sequential sorting will clear the index rsort(); Reverse sorting
asort() ; Sorting by value is not clear, index arsort() ;

• ##ksort(); Sorting by index is not clear, index krsort();

• ##shuffle ();Random sort

• array_reverse(); Reverse the original order of elements

• ##Array pointer operation

• 
  reset(); Point the array pointer to the first element

• end(); Point the array pointer to the last element

• next(); The array pointer moves one position backward

• prev(); The array pointer moves forward one position

• current(); Returns the current element pointed to by the pointer

• Other simple operations on the array

• 
  Array assignment to variables

• list(

• ##item1) = array(' ha','haha','hahaha'); Directly assign the first two elements of the array to variablesQuickly create an array

range( 2,10,2) Create an array from 2 to 10. Each element spans 2
Press the elements in the pop-up array
array_push($arr,'ha','haha') fills the elements into the array
array_pop($arr) will pop the last element of the array and the pointer jumps directly to the first element An element
Change the case of the array index
array_change_key_case($arr,CASE_UPPER/CASE);
Get the intersection between arrays

• ##arr1,$ arr2) intersection with the same value

• ##arr1,$arr2 value and index are both To do the sameExchange the index and element of the array

  array_filp($arr);

• Quickly fill array elements

• array_file(2,10,'haha') Fill a value for the index 2-10

• Calculate the element in The number of occurrences in the array

• array_count_values($arr) generates an array to count how many times each element in the array appears

• Judge the number of occurrences in the array Whether the index exists

• array_key_exists('haha',$arr)

• Get the index in the value

• array_key($arr)

• Traverse each element in the array execution method

• array_map('cube'// Method name, $arr);

• Other functions

• in_array('haha',$arr); Determine whether a value exists in the array Medium

• key('haha',$arr); Get the index of the current element

• ##String processing

• String splitting and merging

---

explode(',',$str,2//Number of segments to split) Split The string is an array

• 
  implode(',',$arr) concatenates the array elements into a string

• of the string Compare and Replace

strcmp(

• 
  

• str2) Compare Whether the two strings are the same returns a bool value

  str_replace('str'//The content to be replaced,

str2The string being replaced); Replace part of the content

• str_replace('haha',

  str2) Single content replacement

• str-replace(

  arr2,$str) Replace multiple words, replace the two arrays one by one

• ##print($str) Output the print string

• String formatting

  
  

• %d Convert to decimal

• %b Convert to binary

• %1.2f is converted into a floating point number and retains two decimal places

• %c is converted into the corresponding ASCLL code

• Convert %s to string

##sprintf('haha%shahahah�hahahah','haha',123)
Placeholder

• 
  

substr(

• ##num1 ,$num2) Intercept a string

  Remove the whitespace characters of the string'

• 
  

trim($str) Remove the blank characters at the beginning and end of the string

• ltrim($str) Remove the blank characters at the beginning of the string

• rtrim($str) Remove the characters The whitespace characters after the string
Convert the characters to upper and lower case

• 
  

  ##strtoupper($str) Convert to upper case

• strtolower($str) Convert to lower case

• ##Prevent the compilation of html tags in the string < -> &it

• 
  htmlentities($str)

• ##Restore tag compilation in string &it -> <

• html_entity_decode($str);
  

• str_repeat($str,3); Repeat to generate one String

str_pad($str,10,”*”,STR_PAD_BOTH/LEFT/RIGHT) Complete the string length by repeating a certain string
str_split($str,3) Split characters into arrays, no length is set, split into single characters by default
String hash encryption

• md5($str1);
  

sha1($str1);

• Operation directories and files

Directory operations

---

Open and close directories

• 
  

• path) Open the directory to obtain the handle closedir($dh) Complete the file operation and close the handle Release resources

• #Get the file name in the next directory in the directory readdir($dh); The parameter is the handle

• Output sequence./../The following is sorted by the first character of the file
  

Get all the files in the directory and put them into the array scandir($path) The parameter is the path
• Modify the location of the current php file

• getcwd() gets the path of the current php
  

chcwd($path) Modify the current php path
• File operation

Open and close files

• r Read only from scratch
  

r Read and write from scratch
w Write only clear the file and create the file from scratch No files
w Read and write clear the file Create the file from scratch
a Write only If it starts from the tail, create
a. For reading and writing, if it starts from the tail, it will create
fopen(

• mode); Open the file to get the handlemode and open the file in the mode

• close($fp); Close the file handle to release resources

  
  

• Read the file

• feof($fp) Determine whether the end of the file is reached
  

fgets($fp,10); Read a line of the file, if there is a second parameter, get the length of the second parameter
Read the entire file
readfile($path) returns the number of bytes in the entire file

• file($path) returns an array, each element is the content of each line

• get_file_content returns the content of the entire file

• Write file
  

• fwrite(

  str,$length) Write file contents

• file_put_contents(

  content) Equivalent to fopen; fwrite(); fclose(); three-in-one

• ##Get file-related information

  
  

• fileowner($path); Returns the file owner`

• filesize($path) gets the file size

• filetype($path) Get the file type

• Function to determine the nature of the file

  
  

• is_dir( $path) Determine whether the path is a folder

• is_file($path) Determine whether the path is a file

• is_readable($path) Determine the file Whether it is readable

• is_wirtable($path) determines whether the file is writable

• Get the file name and directory name of the path

  
  

• basename($path) gets the file name

• dirname($path) gets the name of the directory folder

• file_exists($path) Determine whether the file exists

• Create and delete the folder

  
  

• mkdir($path); Create folder

• rmdir($path); Delete folder

• Create new delete assignment folder

  
  

##copy(

• path2 )Copy the file to the specified path

unlink($path)Delete the file
rename(

• path2) Move files

Lock of file processing (to prevent multiple users from writing at the same time)
flock($fp,[LOCK_EX]); The write lock can only be written by a single person
flock($fp,[LOCK_UN]); Release lock

Change file attributes

• 
  

##chgrp(

• group) Change the group of the file

  chmod($file,0777) Change the file mode

• chown($path,'root'); Change the owner of the file
Get the file time attribute and return the timestamp

• 
  

filetime($path) returns the last access time

• filemtime($path) returns the last file modification time

• filectime($path) Returns the time when the inode was last modified
fgetss($path); Gets the file through http protocol and gets the content to filter out html Tag

• Introduce another php into a php file, similar to the introduction of js files

• 
  

  ##include($path) ;Introduction of files will only give a warning if the file is lost

• require($path);Introduction of files If the file is lost, the entire program will make an error

• # #Processing date and time
Formatting date and time

---

date('Y-m-d H:i:s'); Formatting practice date

• Format characters

• 
  Y year

• mmonth

• d Day

• D Week

• H Hour

• i Minute

• s seconds

• ….

• UNIX timestamp (from 1970 1 The number of seconds calculated starting at 0:00 on the 1st of the month)

• 
  mktime(

• minute,

  month,

  ##year) If the parameter is omitted, the current time is

• date ('M-d-Y',mktime(….));Convert the timestamp into days, minutes and seconds…

• Get the information of all parts of each time and fill it into the array and Return an array

  
  

##getdate([mktime(…)]) to get the current time information or timestamp time information
checkdate(

• day,$year) Determine whether it is valid

For URL and HTTP processing

---

url address analysis

##urlencode($str) Encoding the url is to convert the non-digits and non-letters in the url Into %xx two-digit hexadecimal number

• ##urldecode($str); Convert %xx into the original character

• parse_url($url) returns an array containing various information of the url

• 
  

  scheme protocol

• host host ip address And domain name

• port port number

• pass user name

• pass user password

• path access path

• query query parameter is the information behind the url

• fragment parameter fragment

• Generate HTTP header

header($str) header is used to describe the server communication process and communication time must be in all actual The predefined variables obtained in front of the output

• Get the header information

• 
  

  $_SERVER All server header information array

• $_HTTP_HOST http host

• $_SERVER_NAME server name

• $_SERVER_ADDR server address

• $_SERVER_PORT Server port

• $_SERVER_PROTOCOL Server protocol

• Generate using cookie

setcookie(name //cookie name,[value//cookie value, exprire//cookie expiration time, path//valid path, domain//valid domain name, secure//https secure transmission valid]) Generate cookie

• $_COOKIE['cookiename'] Get cookie

• setcookie('mycookie[love]','yisayu '); Generate array cookie

• setcookie('mycookie','yisayu',time() 60*60)/mktime(0,12,12,45,2017);set Cookie validity period: The cookie will expire after 1 hour. If not set or set to 0, the cookie will expire when the browser is closed.

• The cookie will be sent back to the page in the same directory by default. If you want to send it back to a different page, Pages in the directory

• 
  

  setcookie('mycookie','yisayu',0,'/user/'); will be sent back to all pages in the user directory Page

• setcookie('mycookie',”) Delete cookie

• Mathematical operation

Common Math operations

---

abs($num) absolute value

• ceil($num) ceiling

• floor($num)floor

• sqrt($num) square root

• round($num, 1) rounding The second parameter is reserved Rounding of decimal places

• Decimal conversion

decbin($num) ten to two

• dechex($num) ten to sixteen

• decoct($num) ten to eight

• bindec($num) two to Ten

• octdec($num)eight to ten

• base_convert($num,16,2) Convert num from the base of form To the base of to

• Generate a random number

mt-rand(

• max) Generate random numbers

  Get system information

Get the environment variables to add php

---

Getting php environment variables has the same effect as $_SERVER

• 
  ##getenv('DOCUMENT_ROOT') The environment variable is the file root directory

• getenv('SCRIPT_NAME')Current file

• …..

• putenv('NAME =$env_var');

• View loaded modules

get_load_extensions() Return array

• get_load_extensions_funcs($moudle) Returns a specified module information

• Gets various information of php

phpinfo(); Gets the current php Various information

• getmypid() returns the current pid number

• get_current_user() returns the name of the owner of the current program

Related recommendations:

A brief introduction to the basics of PHP

Basic learning about php

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