PHP Introductory tutorials on Array usage summary (create, delete, traverse, sort etc) _php tips

Source: Internet
Author: User
Tags arrays

The example in this article summarizes the usage of PHP arrays. Share to everyone for your reference, specific as follows:

demo1.php

<?php
  //Create an array variable
  $userNames = Array (' John ', ' Dick ', ' Harry ');
  Print out the array
//echo $userNames;//array
//$userName = ' John ';
echo $userName//John
  ///If you want to print out an element of this array//
  then you must find the subscript for this element, key (key)
  //0,1,2
  //echo $userNames [2];/ /Harry
  //print_r--Print easy to understand information about variables.
  //print_r ($userNames);//array ([0] => John [1] => dick [2] => Harry)
  //$userNames is an array variable, and $userNames [x] Can To understand the small variables under the multivariate
  $userNames [4] = ' Zhao Qi ';
  Print_r ($userNames);//array ([0] => John [1] => dick [2] => Harry [4] => Zhao VII)
?>

demo2.php

<?php
  //range--Creates an array containing the specified range of cells
  //range contains the specified array
  //contains two things, one called a key, and a value
  //key is automatically generated, Default starting from 0, each time +1
  //value is your own assigned value
  //$numbers = range (1,4);
  Print_r ($numbers);  Array ([0] => 1 [1] => 2 [2] => 3 [3] => 4)
//$letters = range (' A ', ' e ');
Print_r ($letters);//array ([0] => a [1] => b [2] => C [3] => D [4] => E)
//Echo $letters [3];
   ?>

demo3.php

<?php
  $userNames = Array (' John ', ' Dick ', ' Harry ');
  Loop to display all values in the array
//for ($i =0 $i <3; $i + +) {
//   Echo ($i + 1). ' --> '. $userNames [$i]. ' <br/> ';
}
   * * 1--> John
   * 2--> Dick *
   3--> Harry
   */
/Echo count ($userNames);//3
//For ($i =0; $i <count ($userNames); $i + +) {
//   Echo ($i + 1). ' --> '. $userNames [$i]. ' <br/> ';
  //If the key does not start at 0, or is not a number at all, then it is not possible to use a listless loop to display the list of data or to
  traverse the array through a Foreach loop, which is beneficial without the need to consider key
//foreach ($userNames as $value) {
//   echo $value. ' <br/> ';
  //foreach traversal $key => $value
//foreach ($userNames as $keyaaa => $value) {
//   echo $keyaaa. ' --> '. $value. ' <br/> ';
/** * 0--> John * 1--> Dick * 2--> Harry * * * * * * * * * */
  /So, you have to make a judgment first
  if (Is_array ($ UserNames)) {
    foreach ($userNames as $key => $value) {
      echo $key. '--> '. $value. ' <br/> ';
    }
  } else{
    echo $userNames;
  }
? >

demo4.php

<?php
  $userNames = Array (' John ', ' Dick ', ' Harry ');
  Print_r ($userNames);
  echo $userNames [0];
? >

demo5.php

<?php//
  Create a custom key (key) array
  //If you do not declare the element key, then compute
//$userNames = Array (' Baidu ' => ' John ', ' Dick ', ' Harry ') from start 0;
//Print_r ($userNames);//array ([Baidu] => John [0] => dick [1] => Harry)
  $userNames = Array (' Baidu ' => ') John ', ' Taobao ' => ' Dick ', ' 360 ' => ' Harry ');
  Print_r ($userNames); Array ([Baidu] => John [Taobao] => Dick [360] => Harry)
  Echo $userNames [' Baidu '];
? >

demo6.php

<?php
  //First create an array of only one element
  $userAge = Array (' CHAOYV ' =>25);
  Print out the Chaoyv age
  //echo $userAge [' chaoyv '];//25
  //Add the previous array, append two, here is the subscript, key, key is a thing
  $userAge [' yike '] = ;
  $userAge [' wife '] =;
  Print_r ($userAge);
? >

demo7.php

<?php
  //array keyword can not be, you can create an array
  $userAges [' chaoyv '] =;
  Print_r ($userAges); Array ([chaoyv] =>)
  $userAges [' yike '] =;
  $userAges [' wife '] =;
  Print_r ($userAges); Array ([chaoyv] => [yike] => [wife] =>)
  //You cannot use a for loop to display all of the data, and you can only traverse it through a foreach
  ( $userAges as $value) {
    echo $value. ' <br/> ';
  }
? >

demo8.php

<?php
//$userAges [' chaoyv '] =;
$userAges [' yike '] =;
$userAges [' wife '] =;
  $username = Array (' => '), ' blood ' => ' Zhao Blood son ', ' learn ' => ' Mo Study ');
  Print_r ($username);
  each use//each-returns the current key/value pair in the array and moves the array pointer forward//
  There is a pointer, by default, the pointer is the first key value pair
  //The first key value right here is ' the world ' => ' how to open '
  //If each ($username), then gets the first key value to the ' world ' => ' How to open '
  //each This function returns an array,
  //each gets the first key value pair, and then wraps it into a new array.
  //print_r (each ($username));
  Equivalent to $a = Array ([1] => how to open [value] => where [0] => World [key] =>)
  //$a = each ($username);
  echo $a [value];
  Print_r (each ($username));
  Echo ' <br/> ';
  Print_r (each ($username));
? >

demo9.php

<?php
  $username = Array (' => '), ' blood ' => ' Zhao Blood son ', ' learn ' => ' Mo Study ');
  Here, how do we use each to loop through all the data?
  //equivalent to $a = Array ([1] => where [value] => open [0] => [key] =>)
  //Two exclamation point, representing real data converted to Boolean
//Echo !! each ($username)//indicates that there is data, there is data, the idea of Boolean values is True (TRUE)
//echo!! each ($username);
Echo!! each ($username);
Echo!! each ($username);//The fourth is a false while
  (!! $a = each ($username)) {
    echo $a [' key ']. ' --> '. $a [' value ']. ' <br/> ';
  }
$a = each ($username);
echo $a [0]. ' ---'. $a [1]. ' <br/> ';
$a = each ($username);
echo $a [0]. ' ---'. $a [1]. ' <br/> ';
$a = each ($username);
echo $a [0]. ' ---'. $a [1]. ' <br/> ';
/**
//*  World---How to open
//*  blood---zhao blood son//*  Learn---MO study/
/*  * * *
?>

demo10.php

<?php
//$usernames = Array (' World ' => ' How to open ', ' blood ' => ' Zhao Blood son ', ' learn ' => ' Mo Study ');
$a = each ($usernames);
World--> Open
//echo $a [' key '];
Echo '--> ';
echo $a [' value '];
$a = each ($usernames);
Blood--> Zhao blood son
//echo $a [' key '];
Echo '--> ';
echo $a [' value '];
List--assigns the values in the array to some variables
//$a = array (' AAA ', ' BBB ', ' CCC ', ' ddd ');  Print_r ($a);//array ([0] => AAA [1] => BBB [2] => CCC [3] => DDD)
//List ($var 1, $var 2, $var 3,$ VAR4) = $a;
echo $var 4;
$usernames = Array (0=> ' How to open ', ' blood ' => ' Zhao Blood son ', ' learn ' => ' Mo Study ');
List can only recognize that the key is numeric////////The
custom string key is not able to use list to identify
//list ($a, $b, $c) = $usernames;
echo $a//why open
  $usernames = Array (' => ', ' => ', ' blood ', ' Zhao Blood son ', ' learn ' => ' Mo Study ');
  Equivalent to $a = Array ([1] => where to open [value] => [0] => [key] =>)
  list ($name, $username) = each ($usernames) ;
  echo $username;
? >

demo11.php

<?php
  $usernames = Array (' => '), ' blood ' => ' Zhao Blood son ', ' learn ' => ' Mo Study ');
  $a =each ($usernames);
  echo $a [key];
  $a =each ($usernames);
  echo $a [key];
  For the third time, I want to take the first array of the array
  //As long as the pointer of the array is adjusted to the first position
  //reset--point the inner pointer of the array to the first unit
  reset ($usernames);
  $a = each ($usernames);
  echo $a [key];
  World Blood
?>

demo12.php

<?php
//$usernames = Array (' World ' => ' How to open ', ' boundary ' => ' How to open ', ' blood ' => ' Zhao Blood son ', ' learn ' => ' mo xue ');
Print_r ($usernames);
Echo ' <br/> ';
Array_unique--The duplicate value in the group is removed////
A new array is created, and the new array has been removed, and the old array is now
//$a = Array_unique ($usernames);
Print_r ($a);
  $numbers = Array (1,24,2,1,3,4,2,6,4,2,4,56,2,4,5);
  Print_r ($numbers);
  $newNumbers = Array_unique ($numbers);
  Print_r ($newNumbers);
? >

demo13.php

<?php
  $usernames = Array (' => ', ' How to open ', ' boundary ' => ' where ', ' blood ' => ' Zhao Blood son ', ' learn ' => ' mo xue ');
  Print_r ($usernames);
  Echo ' <br/> ';
  Array_flip--the key and value
  $newUsernames = Array_flip ($usernames) in the commutative array;
  Print_r ($newUsernames);
  /**
   * Array ([Shi] => how to open [the] => where [blood] => zhao Xue son [xue] => mo xue)
   * Array ([where to open] => [Zhao blood son] => blood [mo xue] = >)
   * */
?>

demo14.php

<?php
  //Create a single array
  $products = Arrays (
    ' Apple ', ' 6 ', ' 28.8 '),
    array (' Pork ', ' 2 ', ' 18.8 '),
    Array (' Cookies ', ' 4 ', ' 48.8 ')
  );
  Print_r ($products);
  Take $products first element out of the
  //print_r ($products [2]);
  Array of Arrays
  echo "|". $products [0][0]. "|". $products [0][1]. "|". $products [0][2]. "| <br/> ";
  echo "|". $products [1][0]. "|". $products [1][1]. "|". $products [1][2]. "| <br/> ";
  echo "|". $products [2][0]. "|". $products [2][1]. "|". $products [2][2]. "| <br/> ";
? >

demo15.php

<?php
  //Create a single array
  $products = Arrays (
    ' Apple ', ' 6 ', ' 28.8 '),
    array (' Pork ', ' 2 ', ' 18.8 '),
    Array (' Cookies ', ' 4 ', ' 48.8 ')
  );
  The length of the outer array is first required
  //echo count ($products);
  For ($i =0 $i <count ($products); $i + +) {for
    ($j =0; $j <count ($products [$i]); $j + +) {
      echo ' | '. $products [$i] [$j];
    }
    echo "|<br/>";
  }
   * * * Apple |6|28.8|
   * | pork |2|18.8|
   * | Biscuit |4|48.8|
   * **/
?>

demo16.php

<?php
  //Create a single array
  $products = arrays (
    ' product ' => ' apple ', ' Quantity ' => ' 6 ', ' Price ' => ' 28.8 '),
    array (' Product ' => ' pork ', ' Quantity ' => ' 3 ', ' Price ' => ' 25.8 '),
    Array (' Product ' => ' cookies ', ' Number ' => ' 2 ', ' Price ' => ' 26.8 '))
  ;
  Print_r ($products)  ;
For ($i =0 $i <count ($products); $i + +) {
//   foreach ($products [$i] as $key => $value) {
//     echo $key. '-$value. ' |   }
//   echo ' <br/> ';
For
  ($i =0 $i <count ($products); $i + +) {while
    !! List ($key, $value) =each ($products [$i])) {
      echo $key. '--'. $value. ' | ';
    }
    Echo ' <br/> ';
  }
  /**
   * Products--Apple | quantity--6| price--28.8|
   * Products--pork | Quantity--3| price--25.8|
   * Products-Biscuit | Quantity--2| price--26.8|
   * * * */
?>

demo17.php

<?php
////sort--array sorting
//$fruit = array (' banner ', ' Orange ', ' apple ');
Before ordering, it is usually shown
////print_r ($fruit) in the order of key;
Sort after
//Sort ($fruit);
Print_r ($fruit);
  $numbers = Array (45,44,27,574,241,7,45,1,5,2,4,5);
  Print_r ($numbers);
  Rsort ($numbers);
  Echo ' <br/> ';
  Print_r ($numbers);
  According to the number, to see the size of the overall number, according to the string, only the first bit size
//$numbers = Array (2,12,3);
Sort ($numbers, sort_numeric);
Print_r ($numbers); Array ([0] => 2 [1] => 3 [2] =>)
//$numbers = Array (2,12,3);
Sort ($numbers, sort_string);
Print_r ($numbers);//array ([0] => [1] => 2 [2] => 3)
?>

demo18.php

<?php
//asort--Sort the array and keep the index relationship
  $fruit = array (' banner ', ' Orange ', ' apple ');
Sort ($fruit);
Print_r ($fruit);
  Array ([0] => Apple [1] => banner [2] => Orange)
  asort ($fruit);
  Print_r ($fruit);
  Array ([2] => Apple [0] => banner [1] => orange)
?>

demo19.php

<?php
  $fruit = Array (' B ' => ' banner ', ' O ' => ' orange ', ' A ' => ' apple ');
  Ksort--the array is sorted according to the key name
  Ksort ($fruit)  ;
  Print_r ($fruit);
  Array ([a] => Apple [b] => banner [o] => orange)
?>

demo20.php

<?php
  //echo '  ';
  Create an array
  $pic = Array (' mm1.jpg ', ' mm2.jpg ', ' mm3.jpg ', ' mm4.jpg ', ' mm5.jpg ');
  The array is randomly disturbed
  //shuffle ($pic);
  Most groups reverse-sort, and the array-preceded function typically creates a new array
  $a = Array_reverse ($pic);
  For ($i =0 $i <3; $i + +) {
    echo ' 

demo21.php

<?php
  $userName = Array (' john ');
  Print_r ($userName);
  The return value of this function will get the number of elements in the current array
  //array_unshift-inserting one or more cells at the beginning of the array
  //inserting data at the beginning
  array_unshift ($userName, ' Dick ')  ;
  Inserts data at the end
  of the Array_push ($userName, ' Wu-ran ');
  Deletes the beginning element
  Array_shift ($userName);
  Deletes the ending element
  Array_pop ($userName);
  Print_r ($userName);
? >

demo22.php

<?php
  $fruit = array (' banner ', ' Orange ', ' apple ');
  This function is used to get the key in an array (key)
  //The second parameter indicates that the fetch of several
//$a = Array_rand ($fruit, 1);
echo $fruit [$a];
  $a = Array_rand ($fruit, 2);
  echo $fruit [$a [0]]. ' '. $fruit [$a [1]];
? >

demo23.php

<?php
  $username = Array (' => '), ' blood ' => ' Zhao Blood son ', ' learn ' => ' Mo Study ');
  By default, the pointer is in the first Data
  //Gets the current element of the pointer, and not moves the pointer to the next
//Echo present ($username);
Echo current ($username);
Echo current ($username);
Echo Next ($username);
Echo current ($username);
Echo Next ($username);
Echo current ($username);
Reset--Points the array's internal pointer to the first unit
//Echo Reset ($username);
echo sizeof ($username);//count
  $numbers = Array (1,4,5,656,7,5,7,4,7,4,5,7);
  Array_count_values--The number of occurrences of the values in the statistical array
  Print_r (Array_count_values ($numbers));
? >

demo24.php

<?php
  $a = $b = $c = ';
  $fruits = Array (' A ' => ' Apple ', ' B ' => ' banner ', ' C ' => ' orange ');
  The string key (key) is set to a variable by a scalar function, and the value is assigned to the variable
  extract ($fruits);
  echo $a;
  echo $c;
  echo $b;
  Appleorangebanner
?>

More interested in PHP related content readers can view the site topics: "PHP array" Operation Tips Encyclopedia, "PHP Basic Grammar Primer", "PHP operation and operator Usage Summary", "PHP object-oriented Program Design Introductory Course", "PHP Network Programming Skills Summary", " Summary of PHP string usage, Introduction to PHP+MYSQL database operations, and a summary of PHP common database operations Tips

I hope this article will help you with the PHP program design.

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