What is passing by object, what is the difference between passing by value and by reference?

I found a similar question, maybe the answer they gave will help you.

Understanding the absence of pointers in Python

In Python everything is an object created in dynamic (automatically maintained) memory. When you call a function, the arguments are passed through their pointers. This is what is known as the object calling convention.

In the other answer, it says this.

In general, objects are stored in the dynamic memory of processes, and variables are references to them: almost almost references are abstractions of pointers, with some more properties.

For this reason, parameter passing is always done by reference, so no pointers are needed for this.

So in a comment they answer this.

false, the passing of parameters is done by value, but they are reference values.

First, definitions (mine, since I come from the world of C++, where there is no passing by name/object, so I adapt the definitions a bit to be able to compare them):

• Object : the chunk of memory. It has a memory address, and no two objects have the same memory address (at least, in C++).
• Value : content or state of an object (ie what is in the chunk of memory).
• Variable : name associated with an object. Distinguishing objects by name is easier than memory addresses, right? To manipulate the variable is to manipulate the object referred to by the variable.
• Reference : name associated with a variable. Manipulating the reference manipulates the object of its associated variable. Equivalent to saying that it is an alternate name for an existing object.

With this, let's move on to the differences (under the assumption that we call a function, whose parameter is received by value, reference or name/object respectively):

• Pass by value : creates a new variable, whose object is a copy of another (two different boxes with the same value/content; assign modifies the content of the local box).

• Pass by reference : a reference to the received variable is created (that is, another name is created for the received object). To manipulate the reference, is to manipulate the "shared object" (two names for the same box; assign modifies the content of the shared box).

• Pass by object (or by name) : a new variable is created, pointing to the received object (two boxes pointing to the same object; assign makes the local box point to a new object, making the original object no longer shared ).

  The difference with the previous one is that, being a new variable, it is reassignable, which means that a = o(if it ais a variable received by name, and oany type of variable or reference), from now on, it makes it apoint to o(a its associated object) without modifying the shared object (which will no longer be shared from now on).

  However, if it awere a reference or a normal variable, a = oit causes the value of the object pointed to by a, to be substituted for the value of the object referred to by o. A reference always shares the object sent when the reference is created, and this cannot be "avoided" or "changed" in any way (a reference cannot become the name of a different box).

  In passing by name, however, each time an assignment is made, the value of the pointed object is not modified, but rather the new object is pointed to, leaving the original object orphaned if it was its "last box" (which then, the garbage collector should take care of deleting).