What's the difference between 'isset()' and '!empty()' in PHP?

Question

I don't understand the difference between isset() and !empty().

Because if a variable has been set, isn't it the same as not being empty?

Have you read the manual for both? [Here](http://www.php.net/isset) and [here](http://www.php.net/empty) — George, Dec 14 '13 at 11:57
Read this http://kunststube.net/isset/ in addition. Thanks @deceze — hek2mgl, Dec 14 '13 at 11:57
`isset();` checks if the variable is literally set, as in the variable actually points to a value something. `empty();` checks if the value the variable points to contains anything. — AlphaDelta, Dec 14 '13 at 11:58

score 74 · Accepted Answer · edited Jul 07 '16 at 20:08

74

ISSET checks the variable to see if it has been set. In other words, it checks to see if the variable is any value except NULL or not assigned a value. ISSET returns TRUE if the variable exists and has a value other than NULL. That means variables assigned a "", 0, "0", or FALSE are set, and therefore are TRUE for ISSET.

EMPTY checks to see if a variable is empty. Empty is interpreted as: "" (an empty string), 0 (integer), 0.0 (float)`, "0" (string), NULL, FALSE, array() (an empty array), and "$var;" (a variable declared, but without a value in a class.

For more information, see this article

edited Jul 07 '16 at 20:08

Michael

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answered Dec 14 '13 at 11:59

Nambi

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" " is not empty. "" is empty. – EresDev Jan 11 '15 at 15:17
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Can you give one example where the isset is true but empty is false. Also an example where isset is false but empty is true? – Unbreakable Sep 02 '15 at 19:41
@Unbreakable, If '$a=true', then `isset()` is true but `empty()` is false. If `$a=null`, then `empty()` is true but `isset()` is false – Istiaque Ahmed Jan 21 '19 at 21:07
I know this is an old question, but is there a difference between `if ($variable) {}` and `if (!empty($variable)) {}` ? – Nathan Jan 15 '21 at 17:35

score 29 · Answer 2 · answered Feb 24 '17 at 06:12

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Source :http://php.net/manual/en/types.comparisons.phpThis page shows the comparison of the empty(),is_null(),isset().

answered Feb 24 '17 at 06:12

Black Mamba

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score 5 · Answer 3 · answered Dec 14 '13 at 12:03

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The type comparison tables gives answer of all question about these operators

http://php.net/manual/en/types.comparisons.php

answered Dec 14 '13 at 12:03

Prashant16

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Andrey P. · Answer 4 · 2017-07-05T10:10:37.983

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And one more remark. empty() checks if the variable exists as well. I.e. if we perform empty() to the variable that wasn't declared, we don't receive an error, empty() returns 'true'. Therefore we may avoid isset() if next we need to check if the variable empty.

So

isset($var) && !empty($var)

will be equals to

!empty($var)

edited Jul 05 '17 at 10:10

answered Jul 05 '17 at 10:04

Andrey P.

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score 0 · Answer 5 · answered Dec 14 '13 at 11:58

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

!empty — Determine whether a variable is NOT empty.

answered Dec 14 '13 at 11:58

user3102083

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`!isset(NULL) === empty(NULL)`. – hek2mgl Dec 14 '13 at 12:03
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So how is "empty" defined? Insufficient explanation. – deceze Dec 14 '13 at 13:22

score 0 · Answer 6 · answered Dec 14 '13 at 13:14

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Isset return false if variable has not been set or it is null and return true if variable has been set and not null.

!empty return true if variable has been set and not empty. Empty string, empty array, "0",0 and false are defined as empty.

answered Dec 14 '13 at 13:14

joy

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What's the difference between 'isset()' and '!empty()' in PHP?

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