[R] R CMD check says no visible binding for global variable

Tue Jan 28 22:24:55 CET 2025

Naresh,

I think your details suggest your earlier request was not well defined.

Your problem looks like this line of code was wrong and did something you did not expect. It should be easy to fix. But I note you changed Prices to use the data.table package. Mind you, I thought the function was lower case setDT and you mention SetDT. At this point, I cannot help you as I do not know enough about the package.

As a general rule, the best way to ask for help includes mentioning the packages you used. The code snippet did not have a library() statement that would be needed.

Here is the original:

Prices[, date = as.Date(date)]

I cannot speak for how data.table might parse that. In base R, it would not work and I can suggest what would.

What you wanted to do was convert a column containing a date in some format into a date in some other format. Am I right? In particular, I am guessing the date returned by SQL into the Prices data.frame is there as text in a standard format. If not, you may need to convert the date some more specific way.

Here is a way outside data.table that might work within it as well.

Prices$date <- as.Date(Prices$date)

The above replaces the contents of one vector/column and note the suggested use is not of “=” which gave you a side-effect, but to use “<-“ in the R-thritic way.

There are other variations and yet more if using the dplyr or other packages, but the above is fairly simple and straightforward and uses base R.

I will spare you further explanations and lecturing on what I thought your code would do as I looked again and realize it is not a standard data.frame anymore.

Here is a test case if your date is in this format:

Prices <- data.frame(date=c("2025-01-01", "2025-01-26"),

                     price=c(12, 14),

                     stock=c("AAPL", "MSFT"))

Prices$date <- as.Date(Prices$date)

The result is:

> Prices

        date price stock

1 2025-01-01    12  AAPL

2 2025-01-26    14  MSFT

If your date is in some other format, you have to specify the format. See the help on as.Date to see how to set the format=option.

If anyone wants to explain better on the data.table method and maybe explain what went wrong, I would be happy to hear it, as well as any corrections on what I wrote.

From: Naresh Gurbuxani <naresh_gurbuxani using hotmail.com> 
Sent: Tuesday, January 28, 2025 1:56 PM
To: John Sorkin <jsorkin using som.umaryland.edu>
Cc: avi.e.gross using gmail.com; r-help using r-project.org
Subject: Re: [R] R CMD check says no visible binding for global variable

Data.frame is returned by SQL query.  It does have column names.  In the function, I make small changes to some columns. 

Something like:

Myquery <- “SELECT date, price, stock FROM stocktab WHERE stock = ‘ABC’ AND date > ‘2025-01-01’;”

Prices <- dbGetQuery(con, myquery)

SetDT(Prices)

Prices[, date = as.Date(date)]

R CMD check say “no visible binding for global variable ‘date’”

Sent from my iPhone

On Jan 28, 2025, at 1:24 AM, Sorkin, John <jsorkin using som.umaryland.edu <mailto:jsorkin using som.umaryland.edu> > wrote:

There you go, once again helping strengthen ;)

John

Get Outlook for iOS <https://aka.ms/o0ukef> 

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From: R-help <r-help-bounces using r-project.org <mailto:r-help-bounces using r-project.org> > on behalf of avi.e.gross using gmail.com <mailto:avi.e.gross using gmail.com>  <avi.e.gross using gmail.com <mailto:avi.e.gross using gmail.com> >
Sent: Tuesday, January 28, 2025 12:01:25 AM
To: 'Naresh Gurbuxani' <naresh_gurbuxani using hotmail.com <mailto:naresh_gurbuxani using hotmail.com> >; r-help using r-project.org <mailto:r-help using r-project.org>  <r-help using r-project.org <mailto:r-help using r-project.org> >
Subject: Re: [R] R CMD check says no visible binding for global variable 

Naresh,

I am not sure how you are creating your data.frame so it has no, I think, column names. There are two scenarios including one where it is not really a valid data.frame and one where it can be handled before any other use as shown below. If it cannot be used, you might need to modify how your SQL or the function you call creates it so it includes either names it chooses or that you supply.

One silly solution if to give your data frame names before using it later. In prticulr, if you know what the columns contain, you can choose suitable names like this if you have exactly three columns:

> colnames(mydata) <- c("first", "second", "third")
> mydata
  first second third
1     1      2     3

If you have a varying number of columns and don't care what the names are, you can make n names that look like temp1, temp2, ... tempn like this:

> paste0("temp", 1:ncol(mydata))
[1] "temp1" "temp2" "temp3"

Obviously, you substitute in whatever your data.frame is called.

So the code to add names for columns looks like:

> colnames(mydata) <- paste0("temp", 1:ncol(mydata))
> mydata
  temp1 temp2 temp3
1     1     2     3

-----Original Message-----
From: R-help <r-help-bounces using r-project.org <mailto:r-help-bounces using r-project.org> > On Behalf Of Naresh Gurbuxani
Sent: Monday, January 27, 2025 5:46 PM
To: r-help using r-project.org <mailto:r-help using r-project.org> 
Subject: [R] R CMD check says no visible binding for global variable

I have written a function which returns an SQL query result as a data.frame.  Each column of data.frame is a variable not explicitly defined.

For every column name, R CMD check says ‘no visible binding for global variable <name>. Status: 1 NOTE

Is it possible to tell R CMD check that these variables are OK?

Thanks,
Naresh

Sent from my iPhone
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