Summary and explanation of PHP array examples_PHP tutorial-PHP Tutorial-php.cn

Summary and explanation of PHP array examples_PHP tutorial

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Release： 2016-07-21 15:25:24

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If you have a large array and all you want to accomplish is to find the presence of a given value, you can use in_array() to return true or false. The following code will output "Not found in this array" because you are looking for an "Alber" that does not exist in $namesArray.

Copy code The code is as follows:

 
$namesArray = array("Joe", "Jane ", "Bob", "Mary", "Paul", "Eddie", "John"); 
$lookingFor = "Albert"; 
if (in_array($lookingFor, $namesArray)) { 
echo "You've found it!"; 
} else { 
echo "Not found in this array!"; 
} 
?> 

If you change the value of $lookingFor to "Mary", you will get the message "You've found it!" because "Mary" is part of $namesArray.
If you want to count the array elements, you can use the count() function:

Copy the code The code is as follows:

 
 $namesArray = array("Joe", "Jane", "Bob", "Mary", "Paul", "Eddie", "John"); 
$count = count($ namesArray); 
?> 

$count value will be 7.
You can add elements to any array, either at the beginning or end of an existing array. You can also use functions to create a new array containing two or more array elements. Each array will be merged as needed. If your array already has internal sorting, you need to reorder the new merged array.
Let us start by adding elements to the end of the existing array, using the function array_push():

Copy the code The code is as follows:

 
/* Create original array*/ 
$fruitArray = array("apple", "orange", "banana", "kiwi", "pear"); 
 /* Add to original array*/ 
array_push($fruitArray, "grape", "pineapple", "tomato"); 
/* List each element by its key value*/ 
while (list($key,$value) = each($fruitArray)) { 
echo "$key : $value
"; 
} 
?> 

This will display:

0 : apple
1 : orange
2 : banana
3 : kiwi
4 : pear
5 : grape
6: pineapple
7: tomato

When you need to add elements to the beginning of the array, the code is very similar, the only difference is the function name: array_unshift() instead of array_push():

Copy code The code is as follows:

 
/* Create original array*/ 
$fruitArray = array("apple ", "orange", "banana", "kiwi", "pear"); 
/* Add to original array*/ 
array_unshift($fruitArray, "grape", "pineapple", "tomato" ); 
/* List each element by its key value*/ 
while (list($key,$value) = each($fruitArray)) { 
echo "$key : $value< br>"; 
} 
?> 

This will display:

0 : grape
1 : pineapple
2 : tomato
3 : apple
4 : orange
5 : banana
6 : kiwi
7 : pear

The function array_merge() merges two or more arrays:

Copy code The code is as follows:

 
/* Create original array*/ 
$ fruitArray = array("apple", "orange", "banana", "kiwi", "pear"); 
$vegArray = array("carrot ", "green beans", "asparagus", "artichoke", "corn"); 
/* Merge into an array*/ 
$goodfoodArray = array_merge($fruitArray, $vegArray); 
/ * List each element by its key value*/ 
while (list($key,$value) = each($goodfoodArray)) { 
echo "$key : $value
"; 
} 
?> 

This will display:

0 : apple
1 : orange
2 : banana
3 : kiwi
4 : pear
5 : carrot
6 : green beans
7 : asparagus
8 : artichoke
9 : corn

Now the array has been processed Adding elements and merging, now let's practice the delete element function. You can use the function array_pop() to delete an element from the end of an array. If you use the function array_shift(), you will delete an element from the beginning of an array. In fact, when you delete from the array element remains available to you when you pop or shift an element from an existing array.
Use the array_pop() function to delete a value from the end of the array:

Copy code The code is as follows:

 
/* Create an array*/ 
$fruitArray = array("apple", "orange", "banana", "kiwi", "pear"); 
/* Pop a value at the end*/ 
$popped = array_pop($fruitArray); 
/* List the contents of the new array and the popped value*/ 
while (list($key, $value) = each($fruitArray)) { 
echo "$key : $value
"; 
} 
echo "
and finally, in $popped: $popped"; 
?> 

This will display:

0 : apple
1 : orange
2 : banana
3 : kiwi
and finally, in $popped: pear
Next, delete an element from the end of an array: ??????????

Next, delete an element from the end of an array: :

Copy code The code is as follows:

 
/* Create an array*/ 
 $fruitArray = array("apple", "orange", "banana", "kiwi", "pear"); 
/* Shift a value from the head of the array*/ 
$shifted = array_shift($fruitArray ); 
/* List the contents of the new array and the removed values*/ 
while (list($key,$value) = each($fruitArray)) { 
echo "$key : $value< ;br>"; 
} 
echo "
and finally, in $shifted: $shifted"; 
?> 

This will show :

0 : orange
1 : banana
2 : kiwi
3 : pear
and finally, in $shifted: apple

There are many functions that can help You sort the array elements. But I will demonstrate basic sorting to help you understand the process:

Copy the code The code is as follows:

 
/* Create original array*/ 
$fruitArray = array("apple", "orange", "banana", "kiwi", "pear"); 
/* Sort*/ 
sort($fruitArray); 
/* Reset it to correctly display the array from beginning to end*/ 
/* List each element by its key value*/ 
while (list($key ,$value) = each($fruitArray)) { 
echo "$key : $value
"; 
} 
?> 

This will display:

0 : apple
1 : banana
2 : kiwi
3 : orange
4 : pear