Example of detecting whether specified characters exist and array length in php array_PHP Tutorial

This tutorial only talks about two places: one is to use the array function in_array to check whether the specified string exists in the array, and the other is to use the count function to determine the length of the array. Definition and usage ​

This tutorial only talks about two places. One is using the array function in_array to check whether the specified string exists in the array, and using the count function to determine the length of the array.
Definition and Usage
The in_array() function searches an array for a given value.

Grammar
in_array(value,array,type)
*/

$os_list=array("mac","nt","irix","linux"); //Define array
if(in_array("irix",$os_list)) //Check whether lrix
exists in the array {
echo "lrix exists in the current operating system list"; //If it exists, output the content
}
echo "
";
if(!in_array("mac",$os_list))
{
echo "mac does not exist in the current operating system list"; //It is case sensitive so this sentence will not be executed
}

/*
in_array Returns true if the given value value exists in the array array. If the third parameter is set to true, the function returns true only if the element exists in the array and has the same data type as the given value.

If the parameter is not found in the array, the function returns false.

Note: If the value parameter is a string and the type parameter is set to true, the search is case-sensitive.

Definition and Usage

Grammar
count(array,mode)

The count() function counts the number of cells in an array or the number of attributes in an object.

For arrays, returns the number of elements, and for other values, returns 1. If the argument is a variable and the variable is not defined, 0 is returned. If mode is set to count_recursive (or 1), the number of array elements in a multidimensional array is recursively counted.

//Array length
*/

$a[0]=1; //Create an array $a[]
by assigning values ​​separately $a[1]=3;
$a[2]=5;
$result=count($a); //Returns the number of elements in array $a 3
echo $result;
echo "
";
$b[0]=7;
$b[5]=9;
$b[10]=11;
$result=count($b); //Returns the number of elements in array $b 3
echo $result;
echo "
";
$result=count(null); //Return 0
echo $result;
echo "
";
$result=count(false); //Return 1
echo $result;

/*
Tips and Notes
Note: When the variable is not set, or the variable contains an empty array, this function returns 0. You can use the isset() variable to test whether a variable is set.

http://www.bkjia.com/PHPjc/445390.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/445390.htmlTechArticleThis tutorial only talks about two places. One is to use the array function in_array to check whether the specified string exists in the array, and Use the count function to determine the length of the array. Definition and usage This tutorial only...