Share This
//PHP isset() vs empty() vs is_null()

PHP isset() vs empty() vs is_null()

Credit: https://techtalk.virendrachandak.com/php-isset-vs-empty-vs-is_null/

 

PHP has different functions which can be used to test the value of a variable. Three useful functions for this are isset()empty() and is_null(). All these function return a boolean value. If these functions are not used in correct way they can cause unexpected results.

isset() and empty() are often viewed as functions that are opposite, however this is not always true. In this post I will explain the differences between these functions.

 

isset()

From PHP manual – isset():

isset — Determine if a variable is set and is not NULL

In other words, it returns true only when the variable is not null.

empty()
From PHP Manual – empty():

empty — Determine whether a variable is empty

In other words, it will return true if the variable is an empty string, false, array(), NULL, “0?, 0, and an unset variable.

is_null()
From PHP Manual – is_null():

is_null — Finds whether a variable is NULL

In other words, it returns true only when the variable is null. is_null() is opposite of isset(), except for one difference that isset() can be applied to unknown variables, but is_null() only to declared variables.

The table below is an easy reference for what these functions will return for different values. The blank spaces means the function returns bool(false).
Value of variable ($var) isset($var) empty($var) is_null($var)
“” (an empty string) bool(true) bool(true)
” ” (space) bool(true)
FALSE bool(true) bool(true)
TRUE bool(true)
array() (an empty array) bool(true) bool(true)
NULL bool(true) bool(true)
“0″ (0 as a string) bool(true) bool(true)
0 (0 as an integer) bool(true) bool(true)
0.0 (0 as a float) bool(true) bool(true)
var $var; (a variable declared, but without a value) bool(true) bool(true)
NULL byte (“\ 0″) bool(true)

 


APPLY NOW






    Benefits

    SALARY & BONUS POLICY

    RiverCrane Vietnam sympathizes staffs' innermost feelings and desires and set up termly salary review policy. Performance evaluation is conducted in June and December and salary change is conducted in January and July every year. Besides, outstanding staffs receive bonus for their achievements periodically (monthly, yearly).

    TRAINING IN JAPAN

    In order to broaden staffs' view about technologies over the world, RiverCrane Vietnam set up policy to send staffs to Japan for study. Moreover, the engineers can develop their career paths in technical or management fields.

    ANNUAL COMPANY TRIP

    Not only bringing chances to the staffs for their challenging, Rivercrane Vietnam also excites them with interesting annual trips. Exciting Gala Dinner with team building games will make the members of Rivercrane connected closer.

    COMPANY'S EVENTS

    Activities such as Team Building, Company Building, Family Building, Summer Holiday, Mid-Autum Festival, etc. will be the moments worthy of remembrance for each individual in the project or the pride when one introduces the company to his or her family, and shares the message "We are One".

    INSURANCE

    Rivercrane Vietnam ensures social insurance, medical insurance and unemployment insurance for staffs. The company commits to support staffs for any procedures regarding these insurances. In addition, other insurance policies are taken into consideration and under review.

    OTHER BENEFITS

    Support budget for activities related to education, entertainment and sports. Support fee for purchasing technical books. Support fee for getting engineering or language certificates. Support fee for joining courses regarding technical management. Other supports following company's policy, etc.

    © 2012 RiverCrane Vietnam. All rights reserved.

    Close