使用两个 for 循环和 if 语句在现有数据框中填充新列

Question

I am trying to "fill" a column of a dataset by combining information by two other columns. More specifically, I am trying the following:

a <- data.frame(gender_p1 = c("man", "woman","man","man"), gender_p2 = c("man", "man","woman","woman"), couple = c(""))
> a
  gender_p1 gender_p2 couple
1       man       man       
2     woman       man       
3       man     woman       
4       man     woman

I want to iterate through a[1] and a[2] to populate respectively a[3] column. I tried to use a double for loop and an ifelse statement within, without any success. Is there any better approach for it? Thanks in advance for any possible proposal.

Answer 1

If your data has not super many rows, check out dplyr (or the tidyverse in general). You can use mutate to create new columns based on some conditions:

a <- data.frame(gender_p1 = c("man", "woman","man","man"), gender_p2 = c("man", "man","woman","woman"))

library(dplyr)

a <- a %>% 
  mutate(same_sex = if_else(
    gender_p1 == gender_p2,
    TRUE,
    FALSE
  ))

a
  gender_p1 gender_p2 same_sex
1       man       man     TRUE
2     woman       man    FALSE
3       man     woman    FALSE
4       man     woman    FALSE