qol (version 1.2.1)

keep_dropp: Keep and Drop Variables Inside a Data Frame

Description

keep() enables you to put in a vector of variable names which then are kept inside the given data frame. All other variables are dropped.

dropp() enables you to put in a vector of variable names which then are dropped from the given data frame. All other variables are kept.

Usage

keep(data_frame, ..., order_vars = FALSE)
dropp(data_frame, ...)

Value

Returns a reduced data table.

Arguments

data_frame

A data frame which should be reduced to (keep) or by (drop) the specified variables.

...

The variable names to keep/drop.

order_vars

keep(): At the end variables are ordered as specified in the command.

Examples

# Example data frame
my_data <- dummy_data(1000)

# Call function
new_dt1 <- my_data |> keep(year, age, sex)
new_dt2 <- my_data |> keep(weight, income, education, sex, order_vars = TRUE)
new_dt3 <- my_data |> dropp(year, age, sex)

# Also works with characters
new_dt4 <- my_data |> keep("year", "age", "sex")
new_dt5 <- my_data |> dropp("year", "age", "sex")

# Or variable names stored as a character vector
var_names <- c("age", "sex", "income", "weight")

new_dt6 <- my_data |> keep(var_names)
new_dt7 <- my_data |> dropp(var_names)

# You can also keep or drop a range of variables
new_dt8 <- my_data |> keep(year, state:income)
new_dt9 <- my_data |> dropp(year, state:income)

# You can also use the colon as a placeholder for any text
start1 <- my_data |> keep("s:") # Variable names start with "s"
start2 <- my_data |> dropp("s:")

end1 <- my_data |> keep(":id") # Variable names end with "id"
end2 <- my_data |> dropp(":id")

contain1 <- my_data |> keep(":on:") # Variable names which contain "on"
contain2 <- my_data |> dropp(":on:")