[R] Question about Rfast colMins and colMaxs

[Stephen H. Dawson, DSL]

Thanks, Richard.

I am researching other library options for data inspection. I have many 
csv files I am reviewing with different column names and data types. 
Flexibility of a quick review of max and min is quite valuable at this 
juncture.

I will implement your code recommendation next week and see how it performs.


Kindest Regards,
*Stephen Dawson, DSL*
/Executive Strategy Consultant/
Business & Technology
+1 (865) 804-3454
http://www.shdawson.com <http://www.shdawson.com>


On 12/2/21 11:06 PM, Richard O'Keefe wrote:
> What puzzles me is why you are not just using
> lapply(some.data.frame, min)
> lapply(some.data.frame, max)
> or as.vector(lapply(...))
> Why go to another package for this?
> Is it the indices you want?
>
> col.min.indices <- function (some.data.frame) {
>     v <- sapply(some.data.frame, function (column)
> which(column == min(column))[1])
>     names(v) <- colnames(some.data.frame)
>     v
> }
>
>
> On Wed, 1 Dec 2021 at 07:55, Stephen H. Dawson, DSL via R-help 
> <r-help using r-project.org <mailto:r-help using r-project.org>> wrote:
>
>     Hi,
>
>
>     I am working to understand the Rfast functions of colMins and
>     colMaxs. I
>     worked through the example listed on page 54 of the PDF.
>
>     https://cran.r-project.org/web/packages/Rfast/index.html
>     <https://cran.r-project.org/web/packages/Rfast/index.html>
>
>     https://cran.r-project.org/web/packages/Rfast/Rfast.pdf
>     <https://cran.r-project.org/web/packages/Rfast/Rfast.pdf>
>
>     My data is in a CSV file. So, I bring it into R Studio using:
>     Data <- read.csv("./input/DataSet05.csv", header=T)
>
>     However, I read the instructions listed on page 54 of the PDF
>     saying I
>     need to bring data into R using a matrix. I think read.csv brings the
>     data in as a dataframe. I think colMins is failing because it is
>     looking
>     for a matrix but finds a dataframe.
>
>      > colMaxs(Data)
>     Error in colMaxs(Data) :
>        Not compatible with requested type: [type=list; target=double].
>      > colMins(Data, na.rm = TRUE)
>     Error in colMins(Data, na.rm = TRUE) :
>        unused argument (na.rm = TRUE)
>      > colMins(Data, value = FALSE, parallel = FALSE)
>     Error in colMins(Data, value = FALSE, parallel = FALSE) :
>        Not compatible with requested type: [type=list; target=double].
>
>     QUESTION
>     What is the best practice to bring a csv file into R Studio so it
>     can be
>     accessed by colMaxs and colMins, please?
>
>
>     Thanks,
>     -- 
>     *Stephen Dawson, DSL*
>     /Executive Strategy Consultant/
>     Business & Technology
>     +1 (865) 804-3454
>     http://www.shdawson.com <http://www.shdawson.com>
>     <http://www.shdawson.com <http://www.shdawson.com>>
>
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