I have a data frame that has multiple sets of pre/post measurements, and I'd like to create a new column for each that calculate the difference (change) in each variable.
Example data
df <- structure(list(Leptin_OVX = c(101537.030773452, 34184.1969018313,
54567.1867690491, 29558.5420636246, 40929.680418857), Leptin_SAC = c(19785.945743781,
124224.32770312, 89539.7367479193, 29335.4677793977, 49085.7085270132
), MIP1A_OVX = c(198.955714001384, 9.39084362457698, 6.31036668689314,
31.4248133610863, 61.7242016227428), MIP1A_SAC = c(152.595958885867,
0, 6.31036668689314, 12.0518867341972, 56.3458462409656), IL4_OVX = c(84.3973038052031,
0, 0, 84.3973038052031, 0), IL4_SAC = c(0, 0, 0, 0, 0), IL1B_OVX = c(20.5433459761151,
0, 0, 0, 26.9522602664794), IL1B_SAC = c(0, 18.9503177384518,
14.986896887192, 0, 0)), row.names = c(NA, -5L), class = c("tbl_df",
"tbl", "data.frame"))
I can do this manually as follows:
df <- df %>%
mutate(chg_Leptin = Leptin_SAC - Leptin_OVX) %>%
mutate(chg_MIP1A = MIP1A_SAC - MIP1A_OVX) %>%
mutate(chg_IL4 = IL4_SAC - IL4_OVX) %>%
mutate(chg_IL1B = IL1B_SAC - IL1B_OVX)
I'm trying to figure out a way to do this in a loop across all the remaining columns were I want to subtract the values from the "_SAC" column from the associated "_OVX" column
Thanks for the help!
We can use across, with some name-changing:
df %>%
mutate(
across(ends_with("_SAC"),
~ .x - get(sub("_SAC$", "_OVX", cur_column())),
.names = "chg_{sub('_SAC$','',.col)}")
)
# # A tibble: 5 × 12
# Leptin_OVX Leptin_SAC MIP1A_OVX MIP1A_SAC IL4_OVX IL4_SAC IL1B_OVX IL1B_SAC chg_Leptin chg_MIP1A chg_IL4 chg_IL1B
# <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl>
# 1 101537. 19786. 199. 153. 84.4 0 20.5 0 -81751. -46.4 -84.4 -20.5
# 2 34184. 124224. 9.39 0 0 0 0 19.0 90040. -9.39 0 19.0
# 3 54567. 89540. 6.31 6.31 0 0 0 15.0 34973. 0 0 15.0
# 4 29559. 29335. 31.4 12.1 84.4 0 0 0 -223. -19.4 -84.4 0
# 5 40930. 49086. 61.7 56.3 0 0 27.0 0 8156. -5.38 0 -27.0