What does it mean when something uses two -> operators in php?

Question

I'm looking at some code here and there are bunch of calls that are like this. I don't have much experience with php, mainly java. Is this like if I had a Dog object that had a fur object and I wanted to call "dog.getFur().getColor();" ?

Example:

  $this->tbtemp_list1->lead_time = ($this->add_lead_time->Text + $this->add_transit_time->Text);
  $this->tbtemp_list1->units = $this->add_units->Text;
  $this->tbtemp_list1->item_class = $this->txtClass->Value;
  $this->tbtemp_list1->category = $this->add_part_category->Text;
  $this->tbtemp_list1->description = $this->add_part_description->Text;
  $this->tbtemp_list1->notes = $this->txtNotes->Text;

You are accessing a sub-object. So the first line `$this->tbtemp_list1` is an object, and you are accessing the `lead_time` property of that object. — DaveRandom, Jan 17 '12 at 18:15
*(related)* http://stackoverflow.com/questions/3737139/reference-what-does-this-symbol-mean-in-php — Gordon, Jan 17 '12 at 18:16

score 2 · Answer 1 · answered Jan 17 '12 at 18:16

2

You are right in your thinking, the -> operator simply accesses a member of an object, such that in $this->tbtemp_list1->lead_time the tbtemp_list1 member of the current object is being accessed, and then the lead_time member of the tbtemp_list1 member.

answered Jan 17 '12 at 18:16

James Shuttler

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score 2 · Answer 2 · answered Jan 17 '12 at 18:16

2

in php

a->b->c is accessing c which is a property or method of b, and b is a child object of a. In javascript, you're just method chaining.

answered Jan 17 '12 at 18:16

Crayon Violent

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Not really familiar with javascript, just java. – davidahines Jan 17 '12 at 18:18

score 1 · Answer 3 · answered Jan 17 '12 at 18:21

Is this like if I had a Dog object that had a fur object and I wanted to call "dog.getFur().getColor();" ?

Yes. The "->" operator in PHP is similar to the "->" operator in C.

In C, it gets a member from a pointer. In PHP, it gets a member from a reference. Since PHP is written in C, I suspect that the syntax for accessing members from objects was directly borrowed from C.

Edit:
It's also good to note here that static members require a different syntax.

print className::$staticVariable;

Nice addition wrt the static member access syntax – James Shuttler Jan 17 '12 at 18:26 — James Shuttler, Jan 17 '12 at 18:26

Jason McCreary · Accepted Answer · 2012-01-17T18:27:25.697

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-> (arrow) is object notation in PHP.

It's equivalent is the . (dot) object notation Java.

For example:

// PHP
$this->tbtemp_list1->lead_time

is:

// Java
this.tbtemp_list1.lead_time

In this case, you are reference a property (lead_time) that is a property of an object lead_time which is a property of an object ($this). This can go on forever provided the property is an object.

edited Jan 17 '12 at 18:27

answered Jan 17 '12 at 18:22

Jason McCreary

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Glad you found this helpful. Ironically my answer was originally deleted by **Robert Harvey**. – Jason McCreary Jan 17 '12 at 20:58

What does it mean when something uses two -> operators in php?

4 Answers4