PHP, how to use instanceof on an array
I did a var_dump on a variable called $row, and I got this:
So I know it is an array. But when I do this:
I get a syntax error: Parse error: syntax error, unexpected 'array' (T_ARRAY).
Now I know there is the is_array, but is there no way I can use instanceof on an array?
array (size=1)
'name' => string 'Glenn' (length=5)
So I know it is an array. But when I do this:
echo $row instanceof array;
I get a syntax error: Parse error: syntax error, unexpected 'array' (T_ARRAY).
Now I know there is the is_array, but is there no way I can use instanceof on an array?
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Apparently not. 'instanceof' is used with objects and classes to determine whether they are members of a specific object or class. 'array' is neither, it is a 'type' in PHP.
http://php.net/manual/en/internals2.opcodes.instanceof.php
http://php.net/manual/en/language.operators.type.php
http://php.net/manual/en/language.types.array.php
http://php.net/manual/en/internals2.opcodes.instanceof.php
http://php.net/manual/en/language.operators.type.php
http://php.net/manual/en/language.types.array.php
There is a lot of terminology (some might say jargon) in object-oriented programming. In OOP parlance, an object in instantiated from a class. The class is the blueprint; the object is the working thing. If I make three objects from the same class definition, I have created three instances of the class. Each of the objects will satisfy the instanceof operator.
http://php.net/manual/en/language.operators.type.php
http://php.net/manual/en/language.operators.precedence.php
Using instanceof is kind of like guessing where your object came from. Using get_class() is kind of like asking where your object came from. I have never found a practical use for these in well-organized object oriented programs, where a common design pattern is "tell, don't ask."
Related:
http://php.net/manual/en/function.is-a.php (a checkered history)
http://php.net/manual/en/function.get-class.php
Some of the broader theory:
http://www.experts-exchange.com/articles/18329/SOLID-Design-in-PHP-Applications.html
http://php.net/manual/en/language.operators.type.php
http://php.net/manual/en/language.operators.precedence.php
Using instanceof is kind of like guessing where your object came from. Using get_class() is kind of like asking where your object came from. I have never found a practical use for these in well-organized object oriented programs, where a common design pattern is "tell, don't ask."
Related:
http://php.net/manual/en/function.is-a.php (a checkered history)
http://php.net/manual/en/function.get-class.php
Some of the broader theory:
http://www.experts-exchange.com/articles/18329/SOLID-Design-in-PHP-Applications.html
It was Dave's answer that led me to the answer when he said 'array' is a type.
Both of you have helped me a lot to date, and I wonder if the days are gone when I'd ask a question and get a very specific answer. It seems I've been getting a slew of links that point to generalities lately, especially from Ray.
Both your responses did help though, but I had to spend a bit more time going through your links. I now know I have to use gettype() first, and if it says object, then I can use getclass() to determine what class it is. gettype() would've also returned 'array' if the variable were an array, which was what I was looking for. Had responses run along these lines, I would've given an 'A' for the solution.
Thank you both for your help.
Both of you have helped me a lot to date, and I wonder if the days are gone when I'd ask a question and get a very specific answer. It seems I've been getting a slew of links that point to generalities lately, especially from Ray.
Both your responses did help though, but I had to spend a bit more time going through your links. I now know I have to use gettype() first, and if it says object, then I can use getclass() to determine what class it is. gettype() would've also returned 'array' if the variable were an array, which was what I was looking for. Had responses run along these lines, I would've given an 'A' for the solution.
Thank you both for your help.
The definition of 'A' grade says "or is a link to information that answered the question". While that is technically correct, you really do take advantage of that as you always give me links that go way beyond the scope of my question. But just because the needle resides in one of the haystacks does not necessarily make a good answer.
I frown upon your practice of changing the grade; this would be the third time you've done this to me. I will have to talk to EE's customer service personnel about this.
I frown upon your practice of changing the grade; this would be the third time you've done this to me. I will have to talk to EE's customer service personnel about this.
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