PHP finds the number of rows in an array

In PHP, arrays are a very common data type, and we often use various functions that operate on arrays. Sometimes, we need to know the number of rows of an array, that is, how many elements it contains. So how to achieve it? This article will introduce several methods to find the number of rows in an array.

Method 1: Use the count() function

PHP provides a built-in function count(), which can be used to count the number of array elements to calculate the number of rows in the array. The specific usage is as follows:

$array = array(1, 2, 3, 4, 5);
$rows = count($array);
echo $rows; //输出：5

In the above code, we first define an array $array containing 5 elements. Then use the count() function to count the number of elements in the array and save the result in the $rows variable. Finally, the value of $rows is output, which is the number of rows in the array.

Method 2: Use the sizeof() function

In addition to the count() function, PHP also provides a similar built-in function sizeof(), which can be used to find the number of array elements. . Regarding the difference between these two functions, you can refer to [PHP Manual](https://www.php.net/manual/en/function.sizeof.php). The method of using the sizeof() function to calculate the number of rows in an array is very similar to the count() function. The code is as follows:

$array = array(1, 2, 3, 4, 5);
$rows = sizeof($array);
echo $rows; //输出：5

Method 3: Using foreach loop

In addition to using built-in functions, we also You can use a foreach loop to count the number of rows in an array. The specific implementation method is to use a counter variable to accumulate the number of traversals during the process of traversing the array, and the final value is the number of rows in the array. The sample code is as follows:

$array = array(1, 2, 3, 4, 5);
$count = 0;
foreach($array as $value){
    $count++;
}
echo $count; //输出：5

In the above code, we first define an array $array containing 5 elements and a counter variable $count. Then iterate through the array through a foreach loop, incrementing the counter by 1 each time it iterates. Finally, the value of the counter is output, which is the number of rows in the array.

Method 4: Use while loop

In addition to using foreach loop, we can also use while loop to count the number of rows in the array. The specific implementation method is to use the PHP built-in function array_shift() in a loop to pop the first element of the array, and determine whether the popped element is empty. If it is empty, jump out of the loop; otherwise, the counter increases by 1. The sample code is as follows:

$array = array(1, 2, 3, 4, 5);
$count = 0;
while($v = array_shift($array)){
    if(empty($v)){
        break;
    }
    $count++;
}
echo $count; //输出：5

In the above code, we first define an array $array containing 5 elements and a counter variable $count. Then use a while loop to iterate through the array. Each time it loops, use the array_shift() function to pop out the first element of the array and determine whether it is empty. If it is empty, jump out of the loop; otherwise, the counter increases by 1. Finally, the value of the counter is output, which is the number of rows in the array.

Summary

This article introduces four methods to solve the number of rows in a PHP array, including using the built-in functions count() and sizeof(), and using foreach loops and while loops. Each of these methods has its own advantages and disadvantages, and they need to be selected based on specific circumstances in practical applications. I hope this article can help readers better understand and master the operation of PHP arrays, as well as some basic programming skills.

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