如何使用 ifelse 使用 mutate 在 R 中获取新列

Question

A simple sample of my data is shown below

 Id xy 12 Yellow Yellow 13 Yellow Blue 10 Blue Yellow 14 Blue Blue 19 Yellow Yellow

And I want to get this

 Id xyz 12 Yellow Yellow Y 13 Yellow Blue N 10 Blue Yellow N 14 Blue Blue N 19 Yellow Yellow Y

When x and y are only Yellow, I get Y, else N for the z column

I have tried this, but it does not help me.

 dat%>% mutate(z=ifelse(x=="Yellow") & (ifelse(y=="yellow")),"Y","N")

Answer 1

We don't need two ifelse . Also, the ifelse for first and second only had the 'test' condition, without the 'yes' or 'no' ie According to ?ifelse , usage is

ifelse(test, yes, no)

In the OP's post, the ifelse got closed after the test condition

ifelse(y=="yellow")
         ^test condition

---

For multiple elements, instead of == , can use %in%

dat$z <- c("N", "Y")[Reduce(`&`, lapply(dat[-1], `%in%`, c('yellow', 'Yellow'))) + 1]
dat$z
#[1] "Y" "N" "N" "N" "Y"

Answer 2

Does this work?

dat %>% mutate(z=ifelse(x=="Yellow" & y == "Yellow", "Y", "N"))

Or maybe this:

dat %>% mutate(z=ifelse(tolower(x)=="yellow" & tolower(y) == "yellow", "Y", "N"))

Answer 3

Here is one base R option without ifelse

transform(
  df,
  z = c("N", "Y")[1 + (rowSums(cbind(x, y) == "Yellow") == 2)]
)

which gives

  Id      x      y z
1 12 Yellow Yellow Y
2 13 Yellow   Blue N
3 10   Blue Yellow N
4 14   Blue   Blue N
5 19 Yellow Yellow Y