Questions tagged [non-standard-evaluation]
156 questions
0
votes
0 answers
Conditionally quote/substitute an expression if not already quoted
I'm looking for a way to quote an argument passed to function (consider substitute(), ggplot2's aes(), subset() or data.table's [ behavior), but do it conditionally - only if not already quoted with quote().
This is because I'd like to easily chain…
mjktfw
- 840
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- 14
0
votes
2 answers
R function to install missing packages
For one of my scripts I want to write an R function that checks if a package is already installed: if so it should use library() to import it in the namespace, otherwise it should install it and import it.
I assumed that pkgname is a string and…
lucacerone
- 9,859
- 13
- 52
- 80
-1
votes
1 answer
How to remove the enclosing brackets when bquote contains multiple expressions?
bquote({
A <- 4
print(A)
})
output:
{
A <- 4
print(A)
}
What can I do so that the output is simply:
A <- 4
print(A)
Bear Bile Farming is Torture
- 4,317
- 4
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- 61
-1
votes
1 answer
Nested functions in parse(eval(...), envir = custom)
I have a custom R environment
e = new.env()
e[["a"]] = function(x) b(x)
e[["b"]] = function(x) x + 1
Function b() runs as expected.
> eval(parse(text = "b(1)"), envir = e)
[1] 2
But a(1) throws an error.
> eval(parse(text = "a(1)"), envir =…
landau
- 5,636
- 1
- 22
- 50
-2
votes
3 answers
How to modify attributes of a variable within data frame inside an R function
The base::levels help file https://stat.ethz.ch/R-manual/R-devel/library/base/html/levels.html contains the following example of modifying the levels of a variable:
z <- gl(3, 2, 12, labels = c("apple", "salad", "orange"))
z
levels(z) <- c("fruit",…
StasK
- 1,525
- 10
- 21
-4
votes
1 answer
How to use dynamic column inside of bquote
a <- "t"
bquote(data.frame(.(a) = 1:10)
Error: unexpected '=' in "bquote(data.frame(.(a) ="
a needs to be dynamic. How can this be accomplished?
Bear Bile Farming is Torture
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