R: Track if an object is copied

track_copy {pryr} | R Documentation

## Track if an object is copied

### Description

The title is somewhat misleading: rather than checking if an object is modified, this really checks to see if a name points to the same object.

### Usage

    track_copy(var, env = parent.frame(), quiet = FALSE)

### Arguments

`var` | variable name (unquoted)
`env` | environment name in which to track changes
`quiet` | if `FALSE`, prints a message on change; if `FALSE` only the return value of the function is used

### Value

a zero-arg function, that when called returns a boolean indicating if the object has changed since the last time this function was called

### Examples

    a <- 1:5
    track_a <- track_copy(a)
    track_a()
    a[3] <- 3L
    track_a()
    a[3] <- 3
    track_a()
    rm(a)
    track_a()

[Package pryr version 0.1.4 Index]