Lecture 3 of 'The Quickest to Understand PHP Programming': PHP Array

Lecture 3 of 'The Quickest to Understand PHP Programming': PHP Array_PHP Tutorial

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Release： 2016-07-21 15:34:11

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Example 7: Basic operations on array values

Copy code The code is as follows:

 
$arr=array ('a'=>"You",'b'=>"I","He"); 
$arr[]="Other"; 
echo $arr['b']. "
"; 
$arr['c']="";//Give a null value, but still occupy the position
echo count($arr)."
" ;//How many values ​​does the array have. 
unset($arr['b']);//This function can unregister strings, entire arrays and other value types and reference types. 
print_r($arr);//This function prints the entire internal structure of numerical and reference types. 
echo "
"; 
foreach($arr as $key=>$value) 
echo $key.":".$value."
";// Loop through the entire array of values. 
?> 

Example 8: Conversion between arrays and strings

Copy code The code is as follows:

 
$arr=array('a'=>"you",'b'=>"I","him"); 
echo $arr =implode('-',$arr);//Array to string, connector - 
echo "
"; 
print_r(explode('-',$arr,2)); //Convert string to array. If the last parameter is not used, it means that all '-'s are divided into arrays
?> 

Example 9: Array sorting

Copy code The code is as follows:

 
$arr=array('b'=>"You",'a'=>"I"," He"); 
ksort($arr);//The array is sorted by the pinyin (UTF-8 encoding) of the key value, and the key value will not be lost. Note that this sort does not return a new array but directly passes the original array as a reference. 
print_r($arr); 
echo "
"; 
asort($arr);//The array is sorted by the pinyin of the value (UTF-8 encoding), and the key value will not be lost. If you don't want key values, you can use the function sort(); if you want to reverse the order, there is also the function rsort(). Note that this sort does not return a new array but directly passes the original array as a reference. 
print_r($arr); 
echo "
"; 
$arr=array(10000,100,1000); 
natsort($arr);//Naturally sort by numbers value, and natcasesort() is not case sensitive
print_r($arr); 
echo "
"; 
print_r(array_reverse($arr));//Array reverse order
 echo "
"; 
?> 

Example 10: Array, random extraction of numbers, number and encoding conversion

Copy code The code is as follows:

 
$arr=array('b'=>"You",'a'=>"I", "him"); 
$key=array_rand($arr,2);//The array randomly selects 2 key values ​​and returns an index array containing the two key values
echo $arr[$key[0] ].$arr[$key[1]]; 
echo "
"; 
echo mt_rand(60,100);//Return a random integer within the range. 
echo "
"; 
echo chr(mt_rand(ord('a'),ord('z')));//Number and encoding conversion. 
echo "
"; 
?> 

That’s it for the array functions. I’ll just pick a few representative ones to get you started. In fact, there are Some uncommon array functions. In addition, we can use for or foreach loops to process arrays and generate our own my_function. There are stupid ways.