Allow locking or protecting a data.table from any modifications #1086

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1. eantonya

   added

   feature request

   on Mar 18, 2015
2. jangorecki commented on Mar 19, 2015

   

   jangorecki

   on Mar 19, 2015

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   maybe we can use drop param?

   # in-place assign by reference
   dt[, a := b]
   dt[, a := b, drop=TRUE]
   # copy `a` column
   dt[, a := b, drop=FALSE]

   This way we can not modify our initial data.table, and have the results materialized as copy. And there is drop finally useful.
3. eantonya commented on Mar 23, 2015

   

   eantonya

   on Mar 23, 2015

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   I think OP wants to prevent semi-accidental modifies, not intentional ones. To achieve what the above drop example does, I'd just use copy now and imo that's easier/more understandable.
4. jangorecki commented on Mar 23, 2015

   

   jangorecki

   on Mar 23, 2015

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   Good point.
   I'm working on package which injects read.only branch functionality into data.table, so user can stick to data.table and prevent not intentional modification. Still it can be improved for [, := ] detection as it now copies the object even if you are not using :=. But one extra copy is a cheap trade-off for locking DT.
5. jangorecki commented on Mar 25, 2015

   

   jangorecki

   on Mar 25, 2015

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   @ClaytonJY I just pushed that functionality into separate package. It allows you to stick to data.table master. jangorecki/dtq will inject same functionality as mentioned data.table branch.
   It is heavy in dev but read.only feature is stable. If you want to use just read.only feature you might want to turn off the main feature of package by options("dtq.log" = FALSE).
6. aryoda commented on Jul 9, 2017

   

   aryoda

   on Jul 9, 2017

   Last edited by aryoda

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   Any news about the state of locking data.tables? I ran into the same requirement, see
   https://stackoverflow.com/questions/44995065/r-how-to-make-a-data-table-read-only-without-copying-it-e-g-for-data-validat

   Update: The package dtq by @jangorecki implements this feature by implicitly copying the data.table, but I would like to avoid making a copy and prefer getting an explicit error so that the developer can recognize the problem (violation of read only data).

   Is it possible to add this feature into the data.table package?

   THX!

   PS: Code snippet in the dtq package (injected into the data.table):

   # read.only mode
       if(isTRUE(attr(x,"read.only",TRUE))){
         x <- copy(x)
         setattr(x,"read.only",NULL)
   }
   

   Source: https://github.com/jangorecki/dtq/blob/master/R/zzz.R
7. aryoda commented on Jul 10, 2017

   

   aryoda

   on Jul 10, 2017

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   This is a (partial?) duplicate of the older #778
8. jangorecki

   changed the title [-][Request] Allow locking or protecting a data.table from any modifications[/-] [+]Allow locking or protecting a data.table from any modifications[/+] on Apr 3, 2020
9. MichaelChirico commented on Apr 14, 2024

   

   MichaelChirico

   on Apr 14, 2024

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   As noted in #778, I'm not sure it's possible to use the lockBinding() mechanism directly -- it's simply too hard to tell in general when an object is locked using the public APIs R provides (please CMIIW).

   However, we could still fulfill this issue with a new function like lockTable() that has a familiar name to lockBinding() but actually works by setting an attribute that assign() can read & respond to.

   This would also get around the back-compatibility flaws of the lockBinding() approach mentioned in #778.
10. MichaelChirico

    added

    top requestOne of our most-requested issuesOne of our most-requested issues

    on Apr 14, 2024