do_repeat: Repeats the same transformations on a specified set of variables/values

Description

Repeats the same transformations on a specified set of variables/values

Usage

do_repeat(data, ...)
.do_repeat(...)
as_is(...)

Arguments

data

data.frame/list. If data is list then do_repeat will be applied to each element of the list.

...

stand-in name(s) followed by equals sign and a vector/list of replacement variables or values. They can be numeric/characters or variables names. Names at the top-level can be unquoted (non-standard evaluation). Quoted characters also considered as variables names. To avoid this behavior use as_is function. For standard evaluation of parameters you can surround them by round brackets. Also you can use %to% operator and other criteria functions. Last argument should be expression in curly brackets which will be evaluated in the scope of data.frame data. See examples.

Value

transformed data.frame data

Details

There is a special constant .N which equals to number of cases in data for usage in expression inside do_repeat. Also there are a variables .item_num which is equal to the current iteration number and .item_value which is named list with current stand-in variables values.

Examples

Run this code

# NOT RUN {
data(iris)
scaled_iris = do_repeat(iris, 
                        i = Sepal.Length %to% Petal.Width, 
                        {
                            i = scale(i)
                        })
head(scaled_iris)

# several stand-in names and standard evaluattion
old_names = qc(Sepal.Length, Sepal.Width, Petal.Length, Petal.Width)
new_names = paste0("scaled_", old_names)
scaled_iris = do_repeat(iris, 
                        orig = ((old_names)), 
                        scaled = ((new_names)), 
                        {
                            scaled = scale(orig)
                        })
head(scaled_iris)

# numerics
new_df = data.frame(id = 1:20)
# note the automatic creation of the sequence of variables
new_df = do_repeat(new_df, 
                   item = i1 %to% i3, 
                   value = c(1, 2, 3), 
                   {
                       item = value
                   })
head(new_df)

# the same result with internal variable '.item_num'
new_df = data.frame(id = 1:20)
new_df = do_repeat(new_df, 
                   item = i1 %to% i3,
                   {
                       item = .item_num
                   })
head(new_df)

# functions
set.seed(123)
new_df = data.frame(id = 1:20)
new_df = do_repeat(new_df, 
                   item = c(i1, i2, i3), 
                   fun = c("rnorm", "runif", "rexp"), 
                   {
                       item = fun(.N)
                   })
head(new_df)


# }