how to solve r error :could not find function "%||%" - r

I keep getting the following error - could not find function %||%. I would like to know what r library() supports %||% and what this function is doing.
Thanks
Leanne

Related

How to debug a "hidden" function in an R package?

can someone please help me understand this:
I encountered an error when calling a function from a library, specifically "steinertree" from the "SteinerNet" package. When stepping into the function with debug(steinertree), I see that the error occurs, when the function in turn calls "steinertree3". When I try debug(steinertree3), I get "object 'steinertree3' not found". Similarly, I can get the code for 'steinertree' by typing it in the terminal, but not for 'steinertree3'.
So it seems to me that there are some "higher-level" functions and "hidden" functions in packages. I did eventually find the error by finding a file "steinertree.R" in the package at CRAN, which contains both 'steinertree' and 'steinertree3', but I`m wondering how to properly go about debugging such "hidden" functions.
Here is a simple example:
library(igraph)
library(SteinerNet)
set.seed(1)
g= erdos.renyi.game(n=10,p.or.m=0.2)
plot(g)
steinertree(type= 'KB', terminals= c(1,3), graph= g)
Thank you!
Use triple colon ::: to execute a function that is not exported by the package/namespace:
package:::hidden_function()

NPV function in r

I am trying to manually add the NPV formula but I am getting the error message Error: attempt to apply non-function
npv<- (2520/(1+0.10))+ (2520(1+0.10)^2)+ (2520(1+0.10)^3)
Please let me know why am I getting this error message and how can I fix this?
Probably, we need the *
(2520/(1+0.10))+ (2520*(1+0.10)^2)+ (2520*(1+0.10)^3)
[1] 8694.229

Parsing error in MonteCarlo::MonteCarlo function in R

I am trying to run a power analysis using a MonteCarlo approach in R.
I have created a function of two parameters that does output a boolean (tested manually for all relevant values of the parameters). I also have run baby-examples of the MonteCarlo function to make sure that I understand it and that it works well.
Yet when I try to run the real thing, I get the following error message:
Error in parse(text = all_funcs_found[i]) : <text>:1:1: unexpected '::'
1: ::
I read through the source code of the MonteCarlo function (which I found here) and found
#loop through non-primitive functions used in func and check from which package they are
for(i in 1:length(all_funcs_found)){
if(environmentName(environment(eval(parse(text=all_funcs_found[i]))))%in%env_names){
packages<-c(packages,env_names[which(env_names==environmentName(environment(eval(parse(text=all_funcs_found[i])))))])
}
}
which doesn't really make sense to me - why should there be a problem there?
Thank you for any ideas.
I found the answer: the function I wrote was calling a function from a specific library in the form libraryname::functionname.
This works OK if you use the function once manually, but makes MonteCarlo break.
I solved the problem by first loading the relevant library, then removing the 'libraryname::' part from the definition of the main function. MonteCarlo then runs just fine.

How can knitr know whether the R code evaluation has error?

The knitr would always evaluate the R code before formatting the output, so just wondering how can I know whether the R code evaluation has error. Thanks
Basically it boils down to three lines of code in the evaluate package. The key is withCallingHandlers(), which can be used to capture errors, messages, and warnings, etc. A minimal example:
withCallingHandlers(1 + 'a', error = function(e) {
cat('An error occurred! The error object is:\n')
str(e)
})
If you don't want the error to halt R, you can wrap the code in try().

Error : could not find function "ImportMethodFrom"

I tried to run the code in Chapter 7 Data mining with R learning with case study book but I got an error in following line:
rankWorkflows(svm, maxs = TRUE)
The error was:
Error in as.character.default(X[[i]], ...) : no method for coercing
this S4 class to a vector
Then I searched on the internet and found following solution:
importMethodsFrom(GenomicRanges, as.data.frame)
and again again I got a new error:
Error: could not find function "importMethodFrom"
I searched a lot but I got nothing :(
You can try using library(sos) to find the packages where your function is located.
library(sos)
findFn("replaceherewithyourfunction")
Based on the answer of #Bea, there does not seem to be a importMethodsFrom anywhere in R. My guess is you found the call in a NAMESPACE file. Those files have different syntax than normal R scripts.
If you want to load a specific function from an R package (rather than all functions from a package), you can use libraryname::functionname instad of functionname in your code. In your case, replace as.data.frame with GenomicRanges::as.data.frame
If this does not work (for example because you don't have as.data.frame anywhere in your code), you can also load the whole GenomicRanges library with library(GenomicRanges)

Resources