Implementation of count multi-dimensional array length statistics in php

For more information about how to implement count multi-dimensional array length statistics in php, see limit. The following program runs the result as () Code: Copy the code below? $ Numbarray (n...

For more information about how to implement count multi-dimensional array length statistics in php, see limit.

The program running result below is ()

The code is as follows:
? $ Numb = array ( Array (10, 15, 30), array (10, 15, 30), array (10, 15, 30) ); Echo count ($ numb, 1 ); A.3 B .12 C.6 D.9

Answer: B

If the mode in the count function is set to COUNT_RECURSIVE (or 1), the number of elements in the array in the multi-dimensional array (that is, the 12 in your result) is calculated recursively ). If the mode is not set, the default value is 0. Multi-dimensional arrays (arrays in arrays) are not detected (result 3 ).

First, traverse the array outside to get two elements ("color1", "color2", "color3") 3
Traverse the array ("color1", "color2", "color3") to get 9 elements
The result is 3 + 9 = 12.

Reference

The code is as follows:
$ Fruits = array ( Array (1, 2, null, null, 5, 6 ), Array (1, 2, null, null, 5, 6 ), ); Echo (count ($ fruits [0]); ?>

You may be talking about arrays defined in other ways, such as directly using:

The code is as follows:
$ Fruits [0] [0] = 1; $ Fruits [0] [3] = 1; $ Fruits [0] [4] = 1; Echo (count ($ fruits [0]); ?>

In this case, 3 is output, because arrays in php do not require the index to be continuous. the reference manual contains the following section:

Array
Arrays in PHP are actually an ordered graph. A graph is a type that maps values to keys. This type has been optimized in many ways, so you can use it as a real array, or a list (vector), a hash (an implementation of a graph), a dictionary, set, stack, queue, and more possibilities. Because another PHP array can be used as the value, and the tree can be easily simulated.

Instance

Obtain the length of the first dimension of a two-dimensional or multi-dimensional array. this is a common program judgment. for example, the array you read is a two-dimensional array:

The code is as follows:
$ Arr = array ( 0 => array ('title' => 'news 1', 'viewnum' => 123, 'content' => 'zaqxswedcrfv '), 1 => array ('title' => 'News 2', 'viewnum' => 99, 'content' => 'qwertyuiopzxcvbnm ') ); ?>

If you want to count the length of the array $ arr, that is to say, the two-dimensional array has only two pieces of news, and the number you want is 2, but if you use different versions of php in count ($ arr, the statistical results are different;
Later, I found in the php manual that the count function has a second parameter, which is explained as follows:
The count function has two parameters:
0 (or COUNT_NORMAL) is the default value. multi-dimensional arrays (arrays in the array) are not detected );
1 (or COUNT_RECURSIVE) is a multi-dimensional array for detection,
Therefore, if you want to determine whether the read array $ arr has news information, write the following statement:

The code is as follows:
If (is_array ($ arr) & count ($ arr, COUNT_NORMAL)> 0) { ..... } Else { ..... } ?>

You can use this code to test the function:

The code is as follows:
$ Arr = array ( 0 => array ('title' => 'news 1', 'viewnum' => 123, 'content' => 'zaqxswedcrfv '), 1 => array ('title' => 'News 2', 'viewnum' => 99, 'content' => 'qwertyuiopzxcvbnm ') ); Echo 'multi-dimensional array not counted:'. count ($ arr, 0); // count ($ arr, COUNT_NORMAL) Echo" "; Echo 'multi-dimensional statistics array: '. count ($ arr, 1); // count ($ arr, COUNT_RECURSIVE) ?>

Now, the first-dimensional length of a two-dimensional or multi-dimensional array in php has been solved.

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