[R] Is there lazy copy in R?

[hadley wickham]

> I don't understand what these addresses mean. Would you please help me
> understand it?

Did you try reading the documentation?

     When an object is traced any copying of the object by the C
     function ‘duplicate’ or by arithmetic or mathematical operations
     produces a message to standard output.  The message consists of
     the string ‘tracemem’, the identifying strings for the object
     being copied and the new object being created, and a stack trace
     showing where the duplication occurred.  ‘retracemem()’ is used to
     indicate that a variable should be considered a copy of a previous
     variable (e.g. after subscripting).

Hadley

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