Reverse Code a Vector (for use in mutate/across)

Vectorized reverse coding for use with dplyr mutate and across.

Usage

reverse_code_vec(x, min = NULL, max = NULL, na.rm = TRUE)

Arguments

x

Numeric vector to reverse code.

min

Numeric. Minimum value of the scale. If NULL (default), detected from data.

max

Numeric. Maximum value of the scale. If NULL (default), detected from data.

na.rm

Logical. Remove NA values when detecting min/max? Default TRUE.

Value

Reverse coded numeric vector.

Details

The reverse coding formula is: reversed = (max + min) - original

For Likert scales, always specify min and max explicitly to ensure correct reversal even when extreme values are not present in the data.

Examples

if (FALSE) { # \dontrun{
library(dplyr)

df <- data.frame(
  item1 = c(1, 2, 3, 4, 5),
  item2 = c(5, 4, 3, 2, 1),
  item3 = c(2, 3, 4, 3, 2)
)

# Reverse single variable (auto-detect scale)
df %>% mutate(item2_r = reverse_code_vec(item2))

# Reverse with explicit 1-5 scale
df %>% mutate(item2_r = reverse_code_vec(item2, min = 1, max = 5))

# Reverse multiple variables
df %>% mutate(across(c(item2, item3), ~reverse_code_vec(.x, min = 1, max = 5), .names = "{.col}_r"))

# 0-10 scale
df %>% mutate(item2_r = reverse_code_vec(item2, min = 0, max = 10))

# 1-7 Likert scale
df %>% mutate(item2_r = reverse_code_vec(item2, min = 1, max = 7))
} # }