Create New Variable by Multiple Conditions via Mutate Case_When

Create new variable by multiple conditions via mutate case_when

The issue is in the use of assignment operator = instead of comparison ==

library(dplyr)
test<- test%>% 
       mutate(WHRcat = case_when((WHR >= 1.02 & sexe == 1) ~ 1,
                                         (WHR < 1.02 & sexe == 1) ~ 2,
                                         (WHR >= 0.85 & sexe == 2) ~ 3,
                                         (WHR < 0.85 & sexe == 2) ~ 4,
                                          TRUE ~ 0)) 

R mutate() with varying multiple conditions given by case_when()

I made a toy example of a for loop mutate case_when with the iris dataset

The first complication is in a simple for (j in 1:10){out<-j} loop, the output data is overwritten with each subsequent iteration of j, and in the end, only the results of the 10th run are retained.

Then I learned about the coalesce() function; which combines (merges? unions? joins?) sparse data of equal length (similar to Microsoft Excel's, paste-special "skip blanks" transformation).

In the sample code below, we take the iris dataset, and loop from 1 to 10, and if iris$Sepal.Length (aka iris[,1]) is equal to the loop iteration j, we change the resulting variable (slope) to 100+j.

iris4 <- tibble(iris)

for (j in 1:10) {
  iris4 <- coalesce(iris4 %>% mutate(Slope = case_when(Sepal.Length == j ~ 100+j)),iris4)}

table(iris4$Slope)

mutate and if_any with condition over multiple columns

The syntax was slightly wrong, but you were close. Note that if_any works like across, so like this if_any(columns, condition), and you should use function, \ or ~ to specify the condition.

df %>% 
  mutate(cod = case_when(if_any(starts_with("string"), ~ .x == "a") ~ 1))

  string1 string2 string3 id cod
1       a       d       a  1   1
2       b       a       d  2   1
3       c       f       c  3  NA

creating new column with case_when when multiple conditions need to be satisfied

Will this work:

df %>%
   mutate(
     flag=case_when(str_detect(record, str_c(code_flag, collapse = '|')) & str_sub(record, start=2, end=2) == "4" & age >=18 ~ "yes", TRUE ~ "no")
   )
  id record age flag
1  1    A4B  12   no
2  1    AAA  12   no
3  2    B45  18   no
4  2    BBB  18   no
5  3   B4A4  22  yes
6  3    CA4  22   no

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