php is null or empty

Question

I have a question regarding NULL in PHP      a         if  a    NULL          echo  is null         Why do I see is null when  a is an empty string  Is that a bug

User · Answer

If you use     php treats an empty string or array as null  To make the distinction between null and empty  either use     or is null  So   if  a     NULL  or if is null  a

User · Answer

check    vs             NULL would return true 0    NULL would return true false    null would return true  where as         NULL would return false 0     NULL would return false false     NULL would return false

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PHP 7 isset   vs empty   vs is null

User · Answer

What you re looking for is   if  variable     NULL          Note the      When use     as you did  PHP treats NULL  false  0  the empty string  and empty arrays as equal

User · Answer

NULL stands for a variable without value  To check if a variable is NULL you can either use is null  var  or the comparison       with NULL  Both ways  however  generate a warning if the variable is not defined  Similar to isset  var  and empty  var   which can be used as functions  var dump is null  var       true var dump  var     null      true var dump empty  var       true  Read more in How to check if a variable is NULL in PHP

User · Answer

This is not a bug but PHP normal behavior  It happens because the    operator in PHP doesn t check for type          null    0    false   If you want also to check if the values have the same type  use     instead  To study in deep this difference  please read the official documentation

User · Answer

Use empty - http   php net manual en function empty php   Example    a       if empty  a         echo  is empty

User · Answer

As is shown in the following table  empty  foo  is equivalent to  foo  null and is null  foo  has the same function of  foo   null  The table also shows some tricky values regarding the null comparison     denotes an uninitialized variables             empty    is null             null     null  isset   array key exists             T       T       F       F       null     T       T       F       T          quot  quot      T       F       T       T                T       F       T       T       0     T       F       T       T         false     T       F       T       T       true     F       F       T       T          1     F       F       T       T          0     F       F       T       T

User · Answer

Just to addon if someone is dealing with  amp nbsp   this would work if dealing with  amp nbsp   Replace it with str replace   first and check it with empty   empty str replace  quot  amp nbsp  quot    quot  quot     YOUR DATA      YOUR DATA    --     YOUR DATA

User · Answer

No it s not a bug  Have a look at the Loose comparisons with    table  second table   which shows the result of comparing each value in the first column with the values in the other columns       TRUE    FALSE   1       0       -1       1       0       -1     NULL    array    php                           FALSE   TRUE    FALSE   TRUE    FALSE   FALSE   FALSE   FALSE   TRUE    FALSE   FALSE   TRUE   There you can see that an empty string    compared with false  0  NULL or    will yield true   You might want to use is null  docs  instead  or strict comparison  third table

[php] php is null or empty?

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