How to define an empty object in PHP

Question

with a new array I do this    aVal   array      aVal key1  var1     something    aVal key1  var2     something else     Is there a similar syntax for an object   object  oVal         oVal- gt key1- gt var1    something    oVal- gt key1- gt var2    something else

User · Answer

You have this bad but usefull technic    var   json decode json encode      FALSE

User · Answer

The standard way to create an  empty  object is    oVal   new stdClass      But  with PHP    5 4  I personally prefer to use    oVal    object       It s shorter and I personally consider it clearer because stdClass could be misleading to novice programmers  i e   Hey  I want an object  not a class         The same with PHP  lt  5 4 is    oVal    object  array         object    is equivalent to new stdClass     See the PHP manual  here       stdClass  Created by typecasting to object    and  here       If an object is converted to an object  it is not modified  If a value of any other type is converted to an object  a new instance of the stdClass built-in class is created      However remember that empty  oVal  returns false  as  PaulP said       Objects with no properties are no longer considered empty    Regarding your example  if you write    oVal   new stdClass     oVal- gt key1- gt var1    something      PHP creates  a Warning here  oVal- gt key1- gt var2    something else     PHP creates the following Warning  implicitly creating the property key1  an object itself      Warning  Creating default object from empty value   This could be a problem if your configuration  see error reporting level  shows this warning to the browser  This is another entire topic  but a quick and dirty approach could be using the error control operator     to ignore the warning    oVal   new stdClass      oVal- gt key1- gt var1    something      the warning is ignored thanks to    oVal- gt key1- gt var2    something else

User · Answer

If you don t want to do this    myObj   new stdClass     myObj- gt key 1    Hello    myObj- gt key 2    Dolly     You can use one of the following    PHP   5 4   myObj    object         key 1    gt   Hello        key 3    gt   Dolly        PHP  lt 5 4   myObj    object  array       key 1    gt   Hello        key 3    gt   Dolly

User · Answer

You can use new stdClass    which is recommended     obj a   new stdClass     obj a- gt name    John   print r  obj a       outputs     stdClass Object    name    gt  John      Or you can convert an empty array to an object which produces a new empty instance of the stdClass built-in class    obj b    object       obj b- gt name    John   print r  obj b       outputs      stdClass Object    name    gt  John       Or you can convert the null value to an object which produces a new empty instance of the stdClass built-in class    obj c    object  null   obj c- gt name    John   print  obj c       outputs     stdClass Object    name    gt  John

User · Answer

php net said it is best    new empty object   new stdClass

User · Answer

If you want to create object  like in javascript  with dynamic properties  without receiving a warning of undefined property   class stdClass    public function   construct array  arguments   array          if   empty  arguments             foreach   arguments as  property   gt   argument                if is numeric  property                     this- gt   argument    null              else                   this- gt   property     argument              endif                     public function   call  method   arguments         arguments   array merge array  stdObject    gt   this    arguments      Note  method argument 0 will always referred to the main class   this       if  isset  this- gt   method    amp  amp  is callable  this- gt   method              return call user func array  this- gt   method    arguments         else           throw new Exception  Fatal error  Call to undefined method stdObject    method                public function   get  name       if property exists  this   name            return  this- gt   name       else          return  this- gt   name    null      endif     public function   set  name   value         this- gt   name     value         obj1   new stdClass   property1   property2   gt  value       assign default property echo  obj1- gt property1   null echo  obj1- gt property2   value   obj2   new stdClass     without properties set echo  obj2- gt property1   null

User · Answer

to access data in a stdClass in similar fashion you do with an asociative array just use the   var  syntax    myObj   new stdClass   myObj- gt Prop1    Something    myObj- gt Prop2    Something else       then to acces it directly  echo  myObj- gt   Prop1    echo  myObj- gt   Prop2        or what you may want  echo  myObj- gt   myStringVar

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I want to point out that in PHP there is no such thing like empty object in sense    obj   new stdClass    var dump empty  obj       bool false    but of course  obj will be empty   On other hand empty array mean empty in both cases   arr   array    var dump empty  arr      Quote from changelog function empty     Objects with no properties are no longer considered empty

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In addition to zombat s answer if you keep forgetting stdClass     function object             return new stdClass             Now you can do    str      array array     object object

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You can also get an empty object by parsing JSON   blankObject  json decode

User · Answer

As others have pointed out  you can use stdClass  However I think it is cleaner without the     like so    obj   new stdClass    However based on the question  it seems like what you really want is to be able to add properties to an object on the fly  You don t need to use stdClass for that  although you can  Really you can use any class  Just create an object instance of any class and start setting properties  I like to create my own class whose name is simply o with some basic extended functionality that I like to use in these cases and is nice for extending from other classes  Basically it is my own base object class  I also like to have a function simply named o    Like so   class o        some custom shared magic  constructor  properties  or methods here    function o       return new o      If you don t like to have your own base object type  you can simply have o   return a new stdClass  One advantage is that o is easier to remember than stdClass and is shorter  regardless of if you use it as a class name  function name  or both  Even if you don t have any code inside your o class  it is still easier to memorize than the awkwardly capitalized and named stdClass  which may invoke the idea of a  sexually transmitted disease class    If you do customize the o class  you might find a use for the o   function instead of the constructor syntax  It is a normal function that returns a value  which is less limited than a constructor  For example  a function name can be passed as a string to a function that accepts a callable parameter  A function also supports chaining  So you can do something like   result  o  internal value - some operation or conversion on this value     This is a great start for a base  language  to build other language layers upon with the top layer being written in full internal DSLs  This is similar to the lisp style of development  and PHP supports it way better than most people realize  I realize this is a bit of a tangent for the question  but the question touches on what I think is the base for fully utilizing the power of PHP

User · Answer

You can try this way also    lt  php       obj   json decode              var dump  obj     gt    Output   object stdClass  1  0

User · Answer

Use a generic object and map key value pairs to it    oVal   new stdClass     oVal- gt key    value   Or cast an array into an object   aVal   array   key   gt  value      oVal    object   aVal

User · Answer

Short answer  myObj   new stdClass        OR    myObj    object         quot foo quot    gt   quot Foo value quot        quot bar quot    gt   quot Bar value quot       Long answer I love how easy is to create objects of anonymous type in JavaScript    JavaScript var myObj         foo   quot Foo value quot       bar   quot Bar value quot     console log myObj foo     Output  Foo value  So I always try to write this kind of objects in PHP like javascript does    PHP  gt   5 4  myObj    object         quot foo quot    gt   quot Foo value quot        quot bar quot    gt   quot Bar value quot        PHP  lt  5 4  myObj    object  array       quot foo quot    gt   quot Foo value quot        quot bar quot    gt   quot Bar value quot      echo  myObj- gt foo    Output  Foo value  But as this is basically an array you can t do things like assign anonymous functions to a property like js does    JavaScript var myObj         foo   quot Foo value quot       bar  function greeting            return greeting    quot  bar quot            console log myObj bar  quot Hello quot       Output  Hello bar    PHP  gt   5 4  myObj    object         quot foo quot    gt   quot Foo value quot        quot bar quot    gt  function  greeting            return  greeting    quot  bar quot            var dump  myObj- gt bar  quot Hello quot       Throw  undefined function  error var dump  myObj- gt bar     Output   quot object Closure  quot   Well  you can do it  but IMO isn t practical   clean   barFunc    myObj- gt bar  echo  barFunc  quot Hello quot      Output  Hello bar  Also  using this synthax you can find some funny surprises  but works fine for most cases

User · Answer

Here an example with the iteration    lt  php  colors    object      colors- gt red     F00    colors- gt slateblue     6A5ACD    colors- gt orange     FFA500    foreach   colors as  key   gt   value      gt       lt p style  background-color  lt     value   gt   gt           lt     key   gt  - gt   lt     value   gt       lt  p gt   lt  php endforeach    gt

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stdClass is the default PHP object  stdClass has no properties  methods or parent  It does not support magic methods  and implements no interfaces   When you cast a scalar or array as Object  you get an instance of stdClass  You can use stdClass whenever you need a generic object instance    lt  php    ways of creating stdClass instances  x   new stdClass   y    object  null            same as above  z    object   a              creates property  scalar     a   a    object  array  property1    gt  1   property2    gt   b      gt    stdClass is NOT a base class  PHP classes do not automatically inherit from any class  All classes are standalone  unless they explicitly extend another class  PHP differs from many object-oriented languages in this respect    lt  php    CTest does not derive from stdClass class CTest       public  property1     t   new CTest  var dump  t instanceof stdClass                 false var dump is subclass of  t   stdClass           false echo get class  t      n                         CTest  echo get parent class  t      n                 false  no parent    gt    You cannot define a class named  stdClass  in your code  That name is already used by the system  You can define a class named  Object    You could define a class that extends stdClass  but you would get no benefit  as stdClass does nothing    tested on PHP 5 2 8

User · Answer

x   new stdClass      A comment in the manual sums it up best      stdClass is the default PHP object    stdClass has no properties  methods or   parent  It does not support magic   methods  and implements no interfaces       When you cast a scalar or array as   Object  you get an instance of   stdClass  You can use stdClass   whenever you need a generic object   instance

[php] How to define an empty object in PHP

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