Summarize object attention points about attributes

Reply content: Reference PHP Document: empty-Check if a variable is empty it is obvious that obj is not empty ~ test: Print_r ($obj); Game Object () empty or non-empty is defined, you do not guess ah ... Objects have been instantiated, then empty is certainly not empty, I understand the emptyempty ("); Trueempty (0); Trueempty (' 0 '); Trueempty (NULL); Trueempty ([]); Trueempty (Array ()); false$a;//only defines unassigned empty ($a);//trueclass AA {} $AA = new AA (); EMP

1. Does the PHP empty object that does not have a property return true?

Introduction: Tested: {code ...}

2. PHP Comparison and logic operations

Summary::P HP comparison and logic operations: 1, the following values with empty () are judged true: unassigned variables, undeclared variables, 0, "0", "", false, NULL, an empty array (), the Magic method of the object __get () The value returned is less than PHP5.0 Version, objects that do not have any properties are also judged to be empty. Note: Empty () accepts only the index or attribute value of a variable or variable, cannot pass in a constant, or pass in an expression, and after PHP 5.5 it supports expression 2, by I

3. PHP comparison and logic operations detailed camera logical logistic regression form logos

Introduction: PHP, Logic: PHP comparison and logical operation of the detailed: 1, the following values with empty () is judged true: Unassigned variable, undeclared variable, 0, "0", "", false, NULL, empty array (), the Magic method of the object __get () The returned value is in a version less than PHP5.0, and the object without any attributes is also judged to be true. Note: Empty () accepts only the index or attribute value of a variable or variable, cannot pass in a constant, or pass in an expression, and after PHP 5.5 it supports expression 2, is

4. eigendecomposition php Empty Check if a variable is empty

Introduction: eigendecomposition:eigendecomposition php empty Check if a variable is empty: empty-Check if a variable is empty report a bug description bool empty (mixed $var) If Var is a non-null or nonzero value, empty () returns FALSE. In other words, "", 0, "0", NULL, FALSE, Array (), Var $var; and objects that do not have any properties will be considered empty and return TRUE if Var is empty. Except when the variable has no value.

5. Empty string exception indicates the difference between empty and isset

Description: Empty string exception Hint: empty string exception hint the difference between empty and isset: Empty is to determine whether a variable is empty, if the variable is non-null or nonzero, then empty () returns FALSE. In other words, "", 0, "0″, NULL, FALSE, Array (), Var $var, undefined, and objects that do not have any properties will be considered empty, and if Var is null, it returns TRUE." (1) Number 0; (2) null character; (3) A variable defined as null; (4) A variable defined as false; (5) an empty array; (6) An undefined variable

6. When PHP detects if a variable is set, empty () can replace isset ()? _php Tutorials

Introduction: When PHP detects whether a variable is set, empty () can replace isset ()? Let's review the empty and isset empty to check if a variable is empty, 0, 0, NULL, FALSE, Array (), Var $var; and objects that do not have any properties will be considered empty, such as

7. The difference between empty () and isset () in PHP

Introduction: 1, empty function Purpose: Detect whether the variable is null judgment: If VAR is a non-null or nonzero value, empty () returns FALSE. In other words, "", 0, "0", NULL, FALSE, Array (), Var $var; and objects that do not have any properties will be considered empty if ...

8. Empty, Isset, is_null differences in PHP

Description: Php empty, isset, is_null difference empty If the variable is a non-null or nonzero value, empty () returns FALSE. In other words, "", 0, "0", NULL, FALSE, Array (), Var $var, undefined; and objects that do not have any properties will be considered empty and return TRUE if Var is empty. Isset returns if the variable exists (not NULL)

9. PHP's empty function that is prone to being used abnormally

Introduction: PHP Easy to use the empty function of the error? In the official PHP manual, write, check if a variable is empty. If Var is a non-null or nonzero value, empty () returns FALSE. In other words, "", 0, "0", NULL, FALSE, Array (), Var $var; and objects that do not have any properties will be considered empty and return TRUE if Var is empty. Then in its hand

PHP easy to use the empty function of the exception

Introduction: PHP Easy to use the empty function of the error? In the official PHP manual, write, check if a variable is empty. If Var is a non-null or nonzero value, empty () returns FALSE. In other words, "", 0, "0", NULL, FALSE, Array (), Var $var; and objects that do not have any properties will be considered empty and return TRUE if Var is empty. It is then solemnly stated in its handbook

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Does php empty object that does not have a property return true?