Questions tagged [standard-evaluation]
24 questions
13
votes
2 answers
standard eval with ggplot2 without `aes_string()`
I'd like to pass a quoted string to a function that calls ggplot2.
library(magrittr); library(ggplot2)
g1 <- function( variable ) {
ggplot(mtcars, aes_string("wt", variable, size="carb")) +
geom_point()
}
g1("mpg")
This works well, but the…
wibeasley
- 5,000
- 3
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- 62
7
votes
1 answer
Scoping of variables in aes(...) inside a function in ggplot
Consider this use of ggplot(...) inside a function.
x <- seq(1,10,by=0.1)
df <- data.frame(x,y1=x, y2=cos(2*x)/(1+x))
library(ggplot2)
gg.fun <- function(){
i=2
plot(ggplot(df,aes(x=x,y=df[,i]))+geom_line())
}
if(exists("i"))…
jlhoward
- 58,004
- 7
- 97
- 140
6
votes
2 answers
How to pass a string to dplyr filter in a function?
I am looking for a way to pass a string as an input to the filter_ function in dplyr package within my own function. I have set up the data frame as follows:
df = data.frame(
X1 = LETTERS[1:5],
X2 = c("apple", "apple", "apple", "banana",…
Jamesm131
- 145
- 1
- 10
4
votes
1 answer
Standard Evaluation with mutate using lazyeval
I'm trying to make my own function wrapping dplyr functions.
I have a list of dataframes and I would like to modify the levels of a specified variable with given labels (both should be function's parameters).
This is what I tried so far…
Julien Navarre
- 7,653
- 3
- 42
- 69
3
votes
2 answers
Dplyr standard evaluation using a vector of multiple strings with mutate function
I am trying to supply a vector that contains multiple column names to a mutate() call using the dplyr package. Reproducible example below:
stackdf <- data.frame(jack = c(1,NA,2,NA,3,NA,4,NA,5,NA),
jill =…
Brandon
- 1,722
- 1
- 19
- 32
3
votes
1 answer
Standard evaluation for tidyr::complete - a function that completes by all non-numeric columns
I want to make a function that would apply tidyr::complete to all non-numeric columns of an R data.frame. Value zero should be inserted to the new value rows. I understand that this requires standard evaluation solution, but I've thus far had no…
Antti
- 1,263
- 2
- 16
- 28
3
votes
1 answer
non-standard evaluation, confusion in advanced R book
So in Hadley's advanced R book, there is an example of an issue with using substitute, here is an excerpt of the code:
subset2 <- function(x, condition) {
condition_call <- substitute(condition)
r <- eval(condition_call, x, parent.frame())
x[r,…
Kun Deng
- 51
- 2
3
votes
2 answers
Change variable name in dplyr::count using standard evaluation
How do I change the name of the grouping variable in dplyr::count_ when it's used in a standard evaluation way
For example if in the final tbl I don't want the var name "Species" but "Type" :
iris %>%
group_by("Species") %>%
…
Julien Navarre
- 7,653
- 3
- 42
- 69
2
votes
2 answers
standard eval with `dplyr::count()`
How can I pass a character vector to dplyr::count().
library(magrittr)
variables <- c("cyl", "vs")
mtcars %>%
dplyr::count_(variables)
This works well, but dplyr v0.8 throws the warning:
count_() is deprecated.
Please use count()…
wibeasley
- 5,000
- 3
- 34
- 62
2
votes
2 answers
Dplyr Multiple Lags Tidy Eval?
I am trying to make multiple lags using the least amount of code possible in dplyr, while sticking to tidy eval. The following Standard Evaluation (SE) code works:
#if(!require(dplyr))…
John
- 312
- 1
- 8
2
votes
1 answer
Standard evaluation and non-standard evaluation in R
I am confused about dplyr functions' arguments and not quite clear about standard evalution (SE) or non-standard evaluation (NSE).
I just want to pass a variable to dplyr::arrange() but it failed. However, passing to dplyr::select() works.
>…
Jackman Li
- 65
- 1
- 8
2
votes
2 answers
Standard Evaluation vs. Non-Standard Evaluation in R package function
It is suggested, that function calls inside R-package functions should preferably use standard evaluation (see here), especially to avoid utils::globalVariables.
If I'm using non-standard evaluation with the dplyr package, what would be the…
Daniel
- 7,252
- 6
- 26
- 38
1
vote
1 answer
How to use non standard evaluation with dollar sign in r
Context
I want to use non-standard evaluation with dollar sign in R.
I want to customize a function with two parameters. data is the input data frame, var is the name of the variable in the input data frame. The return value is the value…
zhiwei li
- 1,635
- 8
- 26
1
vote
1 answer
Using binary operator in lazyeval call with rlang
Let's say I want to add 1 to every value of a column using dplyr and standard evaluation.
I can do :
library(dplyr)
data <- head(iris)
var <- "Sepal.Length"
mutate(data, !!rlang::sym(var) := !!quo(`+`(!!rlang::sym(var), 1)))
But what if I would…
Julien Navarre
- 7,653
- 3
- 42
- 69
1
vote
1 answer
sparklyr and standard evaluation (SE) based functions
I'm trying to write a function that performs and sdf_pivot() a creates a Spark DataFrame with column names that includes the name of the original variable or column.
set.seed(80)
df <- data.frame(id = c(1:5),
var1 =…
guzu92
- 737
- 1
- 12
- 28