update names based on columns-CodePudding

I would like update the names based on two columns

My example has 3 originial columns

df <- data.frame(name1 = c("a", "a", "a", "a", 'a', NA, NA, NA),
                 name2 = c("b", "b", "b", "b", "c", NA, NA, NA),
                 name3 = c("b", "b", "b", "b", "c", "a", "a", "a"))

df
  name1 name2 name3
1     a     b     b
2     a     b     b
3     a     b     b
4     a     b     b
5     a     c     c
6  <NA>  <NA>     a
7  <NA>  <NA>     a
8  <NA>  <NA>     a

I would like to update column name3 (or even create a new column) saying that if name1 == a, and name2 == NA, then the a character in name3 will be replaced by b in column name2.

My desired output something like

  name1 name2 name3
1     a     b     b
2     a     b     b
3     a     b     b
4     a     b     b
5     a     c     c
6  <NA>  <NA>     b
7  <NA>  <NA>     b
8  <NA>  <NA>     b

So far, i am using this df %>% mutate(name3 = ifelse(name1 == "a" & is.na(name2), "b", name3)), but now NA appeared. Any suggestions for this?

CodePudding user response：

We can replace == with %in% to eliminate the NAs, because R evaluates NA %in% x to FALSE, but NA==x to NA

df %>% mutate(name3 = ifelse(name1 %in% 'a' & is.na(name2), 'b', name3))

CodePudding user response：

Base R

df$name3 <- ifelse(any(df$name1 == "a") & is.na(df$name2), "b", df$name3)

`dplyr`

library(dplyr)

df %>% 
  mutate(name3 = case_when(
    any(name1 == "a") & is.na(name2) ~ "b",
    TRUE ~ name3
  ))
#  name1 name2 name3
#1     a     b     b
#2     a     b     b
#3     a     b     b
#4     a     b     b
#5     a     c     c
#6  <NA>  <NA>     b
#7  <NA>  <NA>     b
#8  <NA>  <NA>     b

CodePudding user response：

We could use a case_when or ifelse statement:

library(dplyr)
df %>% 
  mutate(name3 = case_when(any(name1 %in% "a") &
                             is.na(name2) ~ "b",
                           TRUE ~ name3))

or:
df %>% 
  mutate(name3 = ifelse(any(name1 %in% "a") & 
                          is.na(name2), "b", name3))

  name1 name2 name3
1     a     b     b
2     a     b     b
3     a     b     b
4     a     b     b
5     a     c     c
6  <NA>  <NA>     b
7  <NA>  <NA>     b
8  <NA>  <NA>     b