Replacing values of a column in R dataframe - r

Question

I have a data frame named C0001 with 3671 observations of 31 variables. I want to apply a check on each value of one variable named Y. If the value of that variable is greater than 30, then replace it with 30 otherwise keep the existing value. I wrote the following in R but it gives me an error:
C0001 <- read.csv("C0001.csv")
C0001$Y<- ifelse(C0001$Y > 30, 30, C0001$Y)
Error in ans[npos] <- rep(no, length.out = len)[npos] :
replacement has length zero
In addition: Warning message:
In rep(no, length.out = len) : 'x' is NULL so the result will be NULL
Could someone help me with what mistake I am making here? Is there some other way to do the same operation without using ifelse?
Thank you

Answer 1

Try to replace read.csv() with read_csv() as well check your core work directory. The read_csv() function imports data into R as a tibble, while read.csv() imports a regular old R data frame instead. The error indicates that your input is either NULL or a length 0 vector: make sure the indices are correct.
library(readr)
C0001 <- read_csv("C:/Users/Desktop//C0001.csv")
C0001
> C0001
# A tibble: 6 x 3
x y z
<dbl> <dbl> <dbl>
1 2 40 4
2 3 12 5
3 45 12 6
4 1 50 7
5 1 50 30
6 1 0 0
C0001$y<- ifelse(C0001$y > 30, 30, C0001$y)
C0001
# A tibble: 6 x 3
x y z
<dbl> <dbl> <dbl>
1 2 30 4
2 3 12 5
3 45 12 6
4 1 30 7
5 1 30 30
6 1 0 0
Data sample:
structure(list(x = c(2, 3, 45, 1, 1, 1), y = c(30, 12, 12, 30,
30, 0), z = c(4, 5, 6, 7, 30, 0)), row.names = c(NA, -6L), spec = structure(list(
cols = list(x = structure(list(), class = c("collector_double",
"collector")), y = structure(list(), class = c("collector_double",
"collector")), z = structure(list(), class = c("collector_double",
"collector"))), default = structure(list(), class = c("collector_guess",
"collector")), skip = 1L), class = "col_spec"), class = c("spec_tbl_df",
"tbl_df", "tbl", "data.frame"))

Answer 2

Use vectorization like this:
C0001$Y <- C0001$Y[C0001$Y > 30]
This works instead of using ifelse().