A simple analysis of confusing issues regarding length calculation in PHP

This article mainly introduces the confusion about length calculation in PHP, and briefly analyzes PHP’s relevant precautions regarding array and string length operations. Friends in need can refer to the following

often used by PHP I am confused by the character functions of arrays and strings. Here is a summary:

strlen($string) function: Calculate the length of the string;

sizeof ($string,$mode) function: It is an alias of the count() function. The count() function is as follows:

int count (mixed var [, int mode] )

Returns the number of units in var, usually an array, any other type has only one unit.

For objects, if SPL is installed, count() can be called by implementing the Countable interface. This interface has only one method, count(), which returns the return value of the count() function.

If var is not an array type or an object that implements the Countable interface, 1 will be returned, with one exception, if var is NULL the result is 0.

Note:The optional mode parameter is available since PHP 4.2.0.

If the optional mode parameter is set to COUNT_RECURSIVE (or 1), count() will count the array recursively. Particularly useful for computing all elements of multidimensional arrays. The default value for mode is 0. count() does not recognize infinite recursion.

In short, use strlen() for strings and sizeof() for arrays.

Summary: The above is the entire content of this article, I hope it will be helpful to everyone's study.

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