empty function

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Determine whether a variable is considered to be empty. But in my memory, for a long time I thought that empty should be able to judge whether something is empty until one day I am like this "EMPTY (TRIM ($ )) "an error occurs during use, and then

First, both of these functions are used to test the state of a variable: The Isset () function determines if a variable returns true if it is present, otherwise it returns false. The empty () function determines whether a variable is null

$a = 0; ==> compliant with Empty,empty ($a) is true$a = ' 0 '; ==> compliant with Empty,empty ($a) is true$a = "; ==> compliant with Empty,empty ($a) is true$a = "; ==> does not meet empty,empty ($a) for flase$a = null; ==> compliant with

When PHP is developed, when you use empty to check the results returned by a function, you will get an error: Fatal error:can ' t usage function return value in write context For example, the following code: Copy Code code as follows: echo

Source Program header File Contact.h#ifndef _contact_h__#define _contact_h__#define name_max 20#define sex_max 5#define tele_max 15#define ADDR_MAX 50# Define Peo_max 1000#include #include #include typedef struct people{ Char Name[name_max];char

Determine whether a variable is considered to be empty. But for a long time in my memory, I thought empty should be able to judge whether a thing was empty until one day I was like this "empty (trim ($a))" When the use of the error occurred, And

Value. For example. Method 1: CopyCodeThe Code is as follows: $ SQL = "select * Form ABC" $ Result = mysql_query ($ SQL ); $ ROW = mysql_fetch_array ($ result ); If (empty ($ row) // start to judge whether it is null { Echo "null "; }

$ A = '';Echo '1. ----------- '. ($ a = '').' ';Echo '2. ----------- '. ($ a = null).' ';Echo '3. ----------- '. ($ a = false).' ';Echo '4. ----------- '. ($ a = '0').' ';Echo '5. ----------- '. ($ a = 0).' ';$ A = null;Echo '6. ----------- '. (

$a = "; Echo ' 1.---------------'. Empty ($a). ' '; $a = ' 0 '; Echo ' 2.---------------'. Empty ($a). ' '; $a = 0; Echo ' 3.---------------'. Empty ($a). ' '; $a = null; Echo ' 4.---------------'. Empty ($a). ' '; $a = ' null '; Echo ' 5.-----------

During PHP development, when you use empty to check the results returned by a function, the following error occurs: Fatal error: Can't use function return value in write context. For example, the following code:Copy codeThe Code is as follows:Echo

In the development process, often encountered in the judgment of the existence of variables and whether it is empty, especially the array, if the access to a non-existent element of the array, there will be a notice level of error burst, but also a

$a = ';Echo ' 1-----------'. ($a = = ")." ';Echo ' 2-----------'. ($a = = null). ' ';Echo ' 3-----------'. ($a = = false). ' ';Echo ' 4-----------'. ($a = = ' 0 '). ' ';Echo ' 5-----------'. ($a = = 0). ' ';$a = null;Echo ' 6-----------'. ($a =

value to be judged. Very simply, give an example. Method One: Copy Code code as follows: $sql = "SELECT * Form ABC" $result = mysql_query ($sql); $row = Mysql_fetch_array ($result); if (empty ($row))//start to judge is enough empty {

JS Check is a numeric function and a non-empty functionCheck to see if it is not emptyfunction Notempty (obj, msg){str = Obj.value;STR1 = "";for (i = 0; i {if (Str.charat (i)!= ""){STR1 = Str.substr (i, str.length);Break}}if (str1 = ""){Alert

$ A = '';Echo '1. ----------- '. ($ a = '').' ';Echo '2. ----------- '. ($ a = null).' ';Echo '3. ----------- '. ($ a = false).' ';Echo '4. ----------- '. ($ a = '0').' ';Echo '5. ----------- '. ($ a = 0).' ';$ A = null;Echo '6. ----------- '. (

Values to be judged. Very simple, give an example. method One: Copy CodeThe code is as follows: $sql = "SELECT * Form ABC" $result = mysql_query ($sql); $row = Mysql_fetch_array ($result); if (empty ($row))//Start judging is enough empty { echo

$a = "; Echo ' 1.-----------'. ($a = = "). ' '; Echo ' 2.-----------'. ($a = = null). ' '; Echo ' 3.-----------'. ($a = = false). ' '; Echo ' 4.-----------'. ($a = = ' 0 '). ' '; Echo ' 5.-----------'. ($a = = 0). ' '; $a = null; Echo ' 6.-----------

Empty to determine whether a variable is "empty", isset to determine whether a variable has been set. It is this so-called "as the name implies", so I began to take some detours: when a variable value equals 0 o'clock, empty () will also be set

  The code is as follows:Copy code $ Array1 = array ();Print_r ($ array1 );If (empty ($ array1 )){Echo 'for empty () is an empty array (an empty array )';}Else {Echo 'non-empty array (an noempty array) 'for empty )';}?>Display result :###########