Rick,
Oh - setnames already does work on data.frame. That was a change in
v1.8.4.
Was the question more for lists and vectors then (anything that can have
names), rather than just data.frame/data.table?
Matt
On 02/10/13 15:13, Matt Dowle wrote:
On 02/10/13 12:50, Ricky Saporta wrote:
This might be a topic to raise in a separate email:
What do you think of adapting a naming convention where the name of
the function indicates when a function will modify an object by
reference? In my personal work, I have been trying to end such
functions with an underscore. Putting aside for the moment all
obvious and not so obvious issues with changing the names of existing
functions & backwards compatibility, is the idea itself worth
considering?
Maybe. But the convention was already that any function started "set"
indicates it will change the object by reference. The documentation
uses "set*" in several places with this in mind.
> objects("package:data.table", pattern="^set")
[1] "set" "setattr" "setcolorder" "setkey" "setkeyv"
[6] "setnames"
>
If the functions insert() and delete() are added, they'll add and
remove rows by reference. Those verbs don't start with set, but it's
clear (in my mind) that they'd change the data.table by reference;
e.g. insert(DT, row number | "end", some data).
Looking at base etc for functions starting "set*" there's some
side-effect meaning intended there too (setwd, setTimeLimit,
set.seed). setdiff and setequal are about sets in the collection
sense. So it's just setNames as a one off really. And we don't use
camelCase in data.table, so that's how to remember that.
> objects("package:base", pattern="^set")
[1] "setdiff" "setequal" "setHook"
[4] "setNamespaceInfo" "set.seed" "setSessionTimeLimit"
[7] "setTimeLimit" "setwd"
> objects("package:stats", pattern="^set")
[1] "setNames"
> objects("package:utils", pattern="^set")
[1] "setBreakpoint" "setRepositories" "setTxtProgressBar"
Since other set* functions work on data.frame (set() for example!),
setnames should too. I was forgetting that. Let's change it then.
Matt
Rick
Matt
On 01/10/13 20:51, Ricardo Saporta wrote:
Hi All,
I'm wondering if there are any potential problems or unforseen
pitfalls with having
setnames(x, nms)
call
setattr(x, "names", nms)
when x is not a data.table.
Thoughts?
Rick
Ricardo Saporta
Graduate Student, Data Analytics
Rutgers University, New Jersey
e: [email protected] <mailto:[email protected]>
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